CC: ENZYMES

Hepatic disorder, Bone disorder

Clinical significance of Alkaline Phosphatase

Acute pancreatitis

Clinical significance of Amylase

Blood pressure regulation

Clinical significance of Angiotensin-converting enzyme (ACE)

prosthetic group

- A non-protein, but organic, molecule (such as vitamin) that is covalently bound to an enzyme as part of the active site. - When bound tightly to the enzyme, the coenzyme is called a _________________.

LDH-5 (MMMM)

- An LDH isoenzyme that cause elevations in Skeletal muscle injury and is found in skeletal muscle - have greatest clinical significance in the detection of hepatic disorders, particularly intrahepatic disorders. Disorders of skeletal muscle will reveal elevated in these levels, as depicted in the muscular dystrophies. - most labile isoenzyme.

Macroamylasemia

- Condition that results when the AMY molecule combines with immunoglobulins to form a complex that is too large to be filtered across the glomerulus - This condition causes elevated serum amylase because it binds to cold agglutinins and the resulting complex is too big to be filtered in the glomerulus

Alkaline Phosphatase (ALP)

- It belongs to a group of enzymes that catalyze the hydrolysis of various phosphomonoesters at an alkaline pH. - nonspecific enzyme capable of reacting with many different substrates. - functions to liberate inorganic phosphate from an organic phosphate ester with the concomitant production of an alcohol. - highest concentrations are found in the intestine, liver, bone, spleen, placenta, and kidney.

Acid Phosphatase (ACP)

- It belongs to the same group of phosphatase enzymes as ALP and is a hydrolase that catalyzes the same type of reactions. - Functions at an optimal pH of approximately 5.0. - found in the prostate, bone, liver, spleen, kidney, erythrocytes, and platelets. - used as an aid in the detection of prostatic carcinoma, particularly metastatic carcinoma of the prostate.

Alanine aminotransferase (ALT)

- It is a transferase with enzymatic activity similar to that of AST. Specifically, it catalyzes the transfer of an amino group from alanine to a-ketoglutarate with the formation of glutamate and pyruvate. - high concentrations in the liver. - It is considered the more liver-specific enzyme of the transferases.

Amylase (AMS)

- It is an enzyme belonging to the class of hydrolases that catalyze the breakdown of starch and glycogen. - an important enzyme in the physiologic digestion of starches. - produced by acinar cells of the pancreas and the salivary glands - smallest enzyme, because of its small size, it is readily filtered by the renal glomerulus and also appears in the urine.

y-glutamyltransferase (GGT)

- It is an enzyme involved in the transfer of the y-glutamyl residue from y-glutamyl peptides to amino acids, H2O, and other small peptides. In most biologic systems, glutathione serves as the y-glutamyl donor. - involved in peptide and protein synthesis, regulation of tissue glutathione levels, and the transport of amino acids across cell membranes. - found primarily in tissue of the kidney, brain, prostate, pancreas, and liver. - one of the most sensitive of enzyme assays in these conditions

Adenylate Kinase (AK)

- It is an enzyme released from erythrocytes in hemolyzed samples and appearing as a band cathodal to CK-MM. - It may interfere with chemical or immunoinhibition methods, causing a falsely elevated CK or CK-MB value.

Lactate Dehydrogenase (LDH)

- It is an enzyme that catalyzes the interconversion of lactic and pyruvic acids. It is a hydrogen-transfer enzyme that uses the coenzyme NAD+. - High activities are found in the heart, liver, skeletal muscle, kidney, and erythrocytes;

Lipase (LPS)

- It is an enzyme that hydrolyzes the ester linkages of fats to produce alcohols and fatty acids. - catalyzes the partial hydrolysis of dietary triglycerides in the intestine to the 2-monoglyceride intermediate, with the production of long-chain fatty acids. - found primarily in the pancreas, is also present in the stomach and small intestine. - but is considered more specific for pancreatic disorders than AMS measurement.

Coenzymes

- It is an organic cofactor, such as nicotinamide adenine dinucleotide (NAD). - An organic molecule that is a necessary participant in some enzymatic reactions; helps catalysis by donating or accepting electrons or functional groups; e.g., a vitamin, ATP, NAD+.

Glucose-6-phosphate dehydrogenase (G-6-PD)

- It is an oxidoreductase that catalyzes the oxidation of glucose-6-phosphate to 6-phosphogluconate or the corresponding lactone. - The reaction is important as the first step in the pentose-phosphate shunt of glucose metabolism with the ultimate production of NADPH. - tissue sources include the adrenal cortex, spleen, thymus, lymph nodes, lactating mammary gland, and erythrocytes.

Mitochondrial CK (CK-Mi)

- It is bound to the exterior surface of the inner mitochondrial membranes of muscle, brain, and liver. - It migrates to a point cathodal to CK-MM and exists as a dimeric molecule of two identical subunits. - For it to be detected in serum, extensive tissue damage must occur and has been detected in cases of malignant tumor and cardiac abnormalities.

Creatine Kinase (CK)

- It is generally associated with ATP regeneration in contractile or transport systems. - Its predominant physiologic function occurs in muscle cells, where it is involved in the storage of high-energy creatine phosphate. - with highest activities found in skeletal muscle, heart muscle, and brain tissue. - sensitive indicator of acute myocardial infarction (AMI) and muscular dystrophy, particularly the Duchenne type.

Saccharogenic

- Measures the appearance of the product (Starch reducing sugars) - uses a starch substrate that is hydrolyzed by the action of AMS to its constituent carbohydrate molecules that have reducing properties. - the classic reference method for determining AMS activity

Amyloclastic

- Measures the disappearance of starch substrate (Starch-iodine comp. [dark-blue] ↓color intensity) - AMS is allowed to act on a starch substrate to which iodine has been attached. - As AMS hydrolyzes the starch molecule into smaller units, the iodine is released and a decrease occurs in the initial dark-blue color intensity of the starch-iodine complex.

Thymolphthalein monophosphate

- Most specific substrate for prostatic form of acid phosphatase - is the substrate of choice for quantitative endpoint reactions.

Cherry Crandall method

- Reference Method for Lipase Determination - used an olive oil substrate and measured the liberated fatty acids by titration after a 24-h incubation.

Immobilized enzymes

- These are chemically bonded to adsorbents, such as agarose or certain types of cellulose, by azide groups, diazo, and triazine. - convenient for batch analyses and are more stable

CK-MM (CK-3)

- accounts for most of the CK activity in skeletal muscle and heart - is the major isoenzyme fraction found in striated muscle and normal serum. Skeletal muscle contains almost entirely CK-MM.

Vaginal washings

- are examined for seminal fluid-ACP activity, which can persist for up to 4 days. - Elevated activity is presumptive evidence of rape in such cases.

Macroenzymes

- are high-molecular-mass forms of the serum enzymes (ACP, ALP, ALT, amylase, AST, CK, GGT, LDH, lipase) that can be bound to either an immunoglobulin (macroenzyme type 1) or a nonimmunoglobulin substance (macroenzyme type 2). - are usually found in patients who have an unexplained persistent increase of enzyme concentrations in serum.

Turbidimetric methods

- are simpler and more rapid than titrimetric assays. Fats in solution create a cloudy emulsion. - As the fats are hydrolyzed by LPS, the particles disperse, and the rate of clearing can be measured as an estimation of LPS activity.

NAT2 (N-acetyltransferase 2)

- found in liver and GI tract and polymorphisms associated with slow isoniazid metabolism - It is the primary enzyme involved in the acetylation of isoniazid, a drug used to treat tuberculosis.

CK-MB (CK-2)

- has the most specificity for cardiac muscle, even though it accounts for only 3-20% of total CK activity in the heart. - is also found in skeletal muscle - is considered a good indicator of myocardial damage, particularly AMI.

Pharmacogenetic testing

- is often used prior to drug therapy to assist clinicians in identifying patients with genetic polymorphisms, to guide drug and dose selection. - Identifies genetic variations that influence a person's response to drugs - Results provide information to help select drug therapy that is best for the person. - Example: * Warfarin (Coumadin) dose

CK-BB (CK-1)

- small quantity, coupled with its relatively short half-life (1-5 hours), results in its activities that are generally low and transient and not usually measurable when tissue damage occurs. - Highest concentrations are found in the central nervous system, the gastrointestinal tract, and the uterus during pregnancy. - useful tumor-associated marker. - This CK is mainly found in Brain, Bladder, Lung, Prostate, Uterus, Colon, Stomach, Thyroid

CYP2D6

- ultra-metabolizers, extensive metabolizers, intermediate metabolizers, and poor metabolizers. - Patients who are poor metabolizers for this enzyme are at risk for therapeutic failure when inactive prodrugs

Myocardial infarction, Hepatic disorder, Skeletal muscle disorder

Clinical significance of Aspartate amino-transferase (AST)

Chronic pancreatitis insufficiency

Clinical significance of Chymotripsin (CHY)

Myocardial infarction, Skeletal muscle disorder

Clinical significance of Creatine Kinase

Chronic pancreatitis insufficiency

Clinical significance of Elastase-1 (E1)

Drug-induced hemolytic anemia

Clinical significance of Glucose-6-phosphate dehydrogenase (G-6-PD)

Hepatic Disorder

Clinical significance of Glutamate dehydrogenase (GLD)

Hepatic Disorder

Clinical significance of Glutathione-S-transferase (GST)

Acute Myocardial Infarction (AMI)

Clinical significance of Glycogen phosphorylase (GP)

Myocardial infarction, Hepatic disorder, Hemolysis, Carcinoma

Clinical significance of Lactate Dehydrogenase (LDH)

Acute pancreatitis

Clinical significance of Lipase (LPS)

Organophosphate poisoning, Genetic variants, Hepatic disorder, Suxamethonium sensitivity

Clinical significance of Pseudocholinesterase (PChE)

Hemolytic Anemia

Clinical significance of Pyruvate kinase (PK)

Acute pancreatitis

Clinical significance of Trypsin

Skeletal muscle disorder

Clinical significance of aldolase (ALD)

platelet damage

ACP activity in platelets, elevations are observed when _________________ occurs, as in the thrombocytopenia resulting from excessive platelet destruction from idiopathic thrombocytopenic purpura.

pulmonary embolism, congestive heart failure, acute hepatocellular disorders, viral hepatitis, muscular dystrophies, and inflammatory conditions

AST elevations are frequently seen in

fluorometry or colorimetry

After electrophoretic separation, the isoenzymes can be detected either _______________________________

CK-BB (CK-1)

An CK isoenzymes that is elevated in Central nervous system shock, Anoxic encephalopathy, Cerebrovascular accident, Seizure, Placental or uterine trauma, Carcinoma, Reye's syndrome, Carbon monoxide poisoning, Malignant hyperthermia, Acute and chronic renal failure

CK-MB (CK-2)

An CK isoenzymes that is elevated in Myocardial infarction, Myocardial injury, Ischemia, Angina, Inflammatory heart disease, Cardiac surgery, Duchenne-type muscular dystrophy, Polymyositis, Malignant hyperthermia, Reye's syndrome, Rocky Mountain spotted fever, Carbon monoxide poisoning

CK-MM (CK-3)

An CK isoenzymes that is elevated in Myocardial infarction, Skeletal muscle disorder, Muscular dystrophy, Polymyositis, Hypothyroidism, Malignant hyperthermia, Physical activity, Intramuscular injection

LDH-4 (HMMM)

An LDH isoenzyme that cause elevations in Hepatic injury or inflammation and is found in liver

LDH-2 (HHHM)

An LDH isoenzyme that cause elevations in Megaloblastic anemia, Acute renal infarct and Hemolyzed specimen and is found in Heart & RBCs

LDH-1 (HHHH)

An LDH isoenzyme that cause elevations in Myocardial infarction and Hemolytic anemia and also found in Heart and RBCs

LDH-3 (HHMM)

An LDH isoenzyme that cause elevations in Pulmonary embolism, Extensive, Pulmonary pneumonia, Lymphocytosis, Acute pancreatitis, Carcinoma and is found in Lung, Lymphocytes, Spleen, and Pancreas

Isoform

An enzyme molecular form that has been posttranslationally modified.

Hepatic Disorder

Clinical significance of y-Glutamyltransferase (GGT)

Electrophoresis

Analysis of LDH isoenzymes can be accomplished by ___________________ and has been widely used historically.

Cofactors

Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis

Karmen method

Assay methods for AST are generally based on the principle of the ____________, which incorporates a coupled enzymatic reaction using malate dehydrogenase (MD) as the indicator reaction and monitors the change in absorbance at 340 nm continuously as NADH is oxidized to NAD

Chronic alcoholism

Because of the effects of alcohol on GGT activity, elevated GGT levels range from two to three times ULN, may indicate what?

Macro-CK

CK isoenzyme that Migrate midway CK-MM and CK-MB

Oxidoreductases

Catalyze an oxidation-reduction reaction between two substrates

Hydrolases

Catalyze hydrolysis of various bonds

Lyases

Catalyze removal of groups from substrates without hydrolysis; the product contains double bonds

Isomerases

Catalyze the interconversion of geometric, optical, or positional isomers

Ligases

Catalyze the joining of two substrate molecules, coupled with breaking of the pyrophosphate bond in adenosine triphosphate (ATP) or a similar compound

Transferases

Catalyze the transfer of a group other than hydrogen from one substrate to another

CYP5

Catalyzes thromboxane synthesis, including platelet aggregation

hyperplasia of the prostate and prostatic surgery

Causes of ACP elevations

induced fit model

Change in the shape of an enzyme's active site that enhances the fit between the active site and its substrate(s)

Tartrate

Chemical-inhibition methods used to differentiate the prostatic portion most frequently use as inhibitor

Hepatic Disorder

Clinical significance of 5-Nucleotidase

Prostatic carcinoma

Clinical significance of Acid Phosphatase (ACP)

Hepatic Disorders

Clinical significance of Alanine aminotransferase (ALT)

Continuous monitoring

Coupling of several enzyme systems to monitor amylase activity

Bond specificity

Describes the catalyzing of a reaction with a certain type of bond

Salivary AMS

Digestion of starches begins in the mouth with the hydrolytic action, is of short duration because, on swallowing, it is inactivated by the acidity of the gastric contents.

duodenal ulcers and perforated peptic ulcers, intestinal obstruction, and acute cholecystitis

Elevated LPS levels also may be found in

Hepatobiliary disorders (hepatitis and cirrhosis), Biliary tract obstruction, Bone disorders (Paget's disease [osteitis deformans], osteomalacia, rickets, hyperparathyroidism, and osteogenic sarcoma), Pregnancy

Elevations of ALP are of most diagnostic significance in the evaluation of:

lock and key model

Enzymes and substrates fit together based on their specific shapes like a key fits a lock

horseradish peroxidase, alkaline phosphatase, glucose-6-phosphate dehydrogenase, and b-galactosidase

Enzymes are also commonly used as reagents in competitive and noncompetitive immunoassays, such as those used to measure human immunodeficiency virus (HIV) antibodies, therapeutic drugs, and cancer antigens. - Commonly used enzymes include:

acute pancreatitis, diabetes mellitus, and myocardial infarction

GGT levels are also elevated in other conditions, such as:

Warfarin, phenobarbital, phenytoin

GGT levels will be increased in patients receiving enzyme-inducing drugs such as:

hepatocellular disorders and acute inflammatory conditions of the liver

Higher elevations of ALT are found in

Biliary tract obstruction

Higher elevations of GGT are generally observed in ______________________.

6.5 pH

If not assayed immediately, serum should be frozen or acidified to a pH lower than ____. With acidification, ACP is stable for 2 days at room temperature.

RIA, counterimmunoelectrophoresis, and immunoprecipitation

Immunochemical techniques for prostatic ACP use several approaches, including:

LDH flipped pattern

In conditions involving cardiac necrosis (AMI) and intravascular hemolysis, the serum levels of LDH-1 will increase to a point at which they are present in greater concentration than LDH-2.

LDH-1, LDH-3, LDH-4, and LDH-5

In the sera of healthy individuals, the major isoenzyme fraction is LDH-2, followed by ____________________________,

myocardial infarction and megaloblastic anemias

Increased levels of G-6-PD in the serum have been reported in

Noncompetitive inhibitors

It binds an enzyme at a place other than the active site and may be reversible in the respect that some naturally present metabolic substances combine reversibly with certain enzymes. It also may be irreversible if the inhibitor destroys part of the enzyme involved in catalytic activity.

Intramedullary destruction of erythroblasts

It causes elevation as a result of the high concentration of LDH in erythrocytes.

Zymogens

digestive enzymes secreted as inactive proteins, converted to active enzymes by removing some of their amino acids

Ion Exchange Chromatography (IEC)

It has the potential for being more sensitive and precise than electrophoretic procedures performed with good technique. On an unsatisfactory column, however, CK-MM may merge into CK-MB and CK-BB may be eluted with CK-MB. Also, macro-CK may elute with CK-MB.

Serum AMS

It is a mixture of a number of isoenzymes that can be separated on the basis of differences in physical properties, most notably electrophoresis, although chromatography and isoelectric focusing also have been applied.

LDH-6

It is an alcohol dehydrogenase and has been present in patients with arteriosclerotic cardiovascular failure. It is believed that its appearance signifies a grave prognosis and impending death. It may also reflect liver injury secondary to severe circulatory insufficiency.

Uncompetitive inhibition

It is another kind of inhibition in which the inhibitor binds to the ES complex—increasing substrate concentration results in more ES complexes to which the inhibitor binds and, thereby, increases the inhibition.

Aspartate aminotransferase (AST)

It is commonly referred to as a transaminase and is involved in the transfer of an amino group between aspartate and -keto acids. The highest concentrations are found in cardiac tissue, liver, and skeletal muscle.

Activation energy

It is the energy required to raise all molecules in 1 mole of a compound at a certain temperature to the transition state at the peak of the energy barrier.

Acetylation

It is the primary mechanism for the elimination of isoniazid and, therefore, patients with low NAT2 activity will not be able to inactivate isoniazid, putting those patients at increased risk for adverse drug reactions.

red cell hemolysate

It is used to assay for deficiency of the enzyme; serum is used for evaluation of enzyme elevations.

LDH-1

It migrates most quickly toward the anode, followed in sequence by the other fractions, with LDH-5 migrating the slowest.

Stereoisometric specificity

It refers to enzymes that predominantly combine with only one optical isomer of a certain compound.

viral hepatitis, cirrhosis, AMI, pulmonary infarct

It shows slight elevations of two to three times ULN LDH.

25°C; 48 hours

LDH activity is unstable in serum regardless of the temperature at which it is stored. If the sample cannot be analyzed immediately, it should be stored at ________ and analyzed within ________.

plasma

Macroenzymes accumulate in _________ because their high molecular masses prevent them from being filtered out of the plasma by the kidneys.

continuous-monitoring or kinetic assays

Multiple measurements, usually of absorbance change, are made during the reaction, either at specific time intervals (usually every 30 or 60 seconds) or continuously by a continuous-recording spectrophotometer. Advantageous because the linearity of the reaction may be more adequately verified.

Chromogenic

Measures the increasing color from production of product coupled with a chromogenic dye - use a starch substrate to which a chromogenic dye has been attached, forming an insoluble dye-substrate complex. - As AMS hydrolyzes the starch substrate, smaller dye-substrate fragments are produced, and these are water soluble.

electrophoresis, ion-exchange chromatography and several immunoassays, including radioimmunoassay (RIA) and immunoinhibition methods.

Methods used for measurement of CK isoenzymes include:

7.0 to 8.0

Most physiologic enzymatic reactions occur in the pH range of __________

fixed-time and continuous-monitoring or kinetic assay

One of two general methods may be used to measure the extent of an enzymatic reaction:

acute pancreatitis, mumps, parotitis, perforated peptic ulcer, intestinal obstruction, cholecystitis, ruptured ectopic pregnancy, mesenteric infarction, acute appendicitis, renal insufficiency and diabetic ketoacidosis

Other disorders causing an elevated serum AMS level include

UGT1A1

Phase II metabolism common polymorphism involves extra repeats in promoter region -irinotecan to SN38 which is shut off by UGT1A1, both have activity -conjugates bilirubin Gilbert's syndrome 60% active Crigler Najjar 1 No activity, fatal if not treated. Blood, liver transplant Crigle Najjar 2 10% active, phototherapy

estimation of liberated fatty acids and turbidimetric methods

Procedures used to measure LPS activity include:

2 days at 4°C

RIA procedures for measurement of prostatic ACP require nonacidified serum samples. Activity is stable for ________________.

Electrophoresis

Reference methof for CK-MB

CK-BB (CK-1), CK-MB (CK-2), CK-MM (CK-3)

Sequence of isoenzymes of CK on electrophoretic separation (starting with the fastest)

Paget's disease, in breast cancer with bone metastases, and in Gaucher's disease

Serum ACP activity may frequently be elevated in

1-2 hours

Serum activity decreases within ____________ if the sample is left at room temperature without the addition of a preservative. Decreased activity is a result of a loss of carbon dioxide from the serum, with a resultant increase in pH.

red cells

Serum should be separated from the ______________ as soon as the blood has clotted to prevent leakage of erythrocyte and platelet ACP.

Duchenne-type muscular dystrophy, cerebrovascular accident, seizures, nerve degeneration, and central nervous system shock, hypothyroidism, malignant hyperpyrexia, and Reye's syndrome

Striking elevations of Creatine Kinase occur in

a-naphthyl phosphate

Substrate for continuous monitoring method of ACP determination

pernicious anemia and hemolytic disorders

The highest levels of total LDH are seen in

y-glutamyl-p-nitroanilide

The most widely accepted substrate for use in GGT analysis. The reaction, which can be used as a continuous-monitoring or fixed-point method,

9.0 to 10.0

The optimal pH of ALP for the reaction is _________, but optimal pH varies with the substrate used. The enzyme requires Mg2+ as an activator.

protein electrophoresis

The principal method to identify enzymes that are bound to immunoglobulins and nonimmunoglobulins

fixed time method

The reactants are combined, the reaction proceeds for a designated time, the reaction is stopped (usually by inactivating the enzyme with a weak acid), and a measurement is made of the amount of reaction that has occurred. The reaction is assumed to be linear over the reaction time; the larger the reaction, the more enzyme is present.

dark place at 4°C

The serum that will used for CK activity should be stored in a ___________ because CK is inactivated by light.

coupled enzymatic reaction using LDH as the indicator enzyme

The typical assay procedure for ALT consists of a __________________________________, which catalyzes the reduction of pyruvate to lactate with the simultaneous oxidation of NADH. The change in absorbance at 340 nm measured continuously is directly proportional to ALT activity.

Troponin I and Troponin T

They have been used as a more sensitive and specific marker of myocardial damage. These proteins are released into the bloodstream earlier and persist longer than CK and its isoenzyme CK-MB.

Hemolysis

This type of sample should be avoided because it can dramatically increase serum AST concentration.

Hemolysis

Type of sample which does not interfere with GGT levels because the enzyme is lacking in erythrocytes.

Colorimetric methods

Used to measure LPS activity and are also available and are based on coupled reactions with enzymes such as peroxidase or glycerol kinase.

metallic (Ca2+, Fe2+, Mg2+, Mn2+, Zn2+, and K) and nonmetallic (Br- and Cl-)

What are the common activators?

chloride or magnesium ions

What are the examples of inorganic cofactor?

Hemolysis

What sample should be avoided as the hemoglobin inhibits the activity of serum LPS, causing falsely low values?

Hemolyzed serum

What type of samples that may be a source of elevated CK activity?

Cofactors

are nonprotein entities that must bind to particular enzymes before a reaction occurs.

Enzymes

are protein catalysts utilized by essentially all mammalian cells in specific biochemical reactions in different organs of the body (different organelles and structures within a cell).

Allosteric site

a cavity other than the active site; binds the regulator molecules

Holoenzyme

apoenzyme + cofactor

prostate-specific antigen (PSA)

blood test that measures the level of prostate-specific antigen in the blood

CYP24

catalyzes the hydroxylation and inactivation vitamin D3.

Isoenzymes

cell enzymes, specific to certain organs, that differ slightly in structure, but have similar functions

Group specific

enzymes that are combine with all substrates containing a particular chemical group, such as a phosphate ester.

Cytochrome P450

enzymes that function to metabolize potentially toxic compounds, including drugs and products of endogenous metabolism such as bilirubin, principally in the liver.

Dextrins

fragments of the amylopectin molecule containing a 1,6 bond that amylase cannot digest

Antibodies against both the M and B subunits

have been used to determine CK-MB activity. Anti-M inhibits all M activity but not B activity. CK activity is measured before and after inhibition. Activity remaining after M inhibition is a result of the B subunit of both MB and BB activity. - major disadvantage is that it detects BB activity, which, although not normally detectable, will cause falsely elevated MB results when BB is present.

ACP assays

have proved useful in forensic clinical chemistry, particularly in the investigation of rape.

Activators

increase the activity of enzymes

Thiopurine Methyltransferase (TPMT)

is an enzyme that can be found in bone marrow and erythrocytes and functions to inactivate chemotherapeutic thiopurine drugs like azathioprine and 6-mercaptopurine. - Patients with low activity are at risk of developing severe bone marrow toxicity when the standard dose therapy for thiopurine drugs is administered;

Bowers and McComb

method for detection of ALP which is a continuous-monitoring technique that allows calculation of ALP activity based on the molar absorptivity of p-nitrophenol.

bedridden

patients who are ______________ for prolonged periods may have decreased CK activity.

Pancreatic AMS

performs the major digestive action of starches once the polysaccharides reach the intestine.

Competitive inhibitors

physically bind to the active site of an enzyme and compete with the substrate for the active site.

Apoenzyme

protein portion of enzyme (inactive)

Coenzymes

serve as second substrates for enzymatic reactions.

Absolute specificity

the enzyme combines with only one substrate and catalyzes only the one corresponding reaction.

enzyme-substrate (ES) complex

the substrate readily binds to free enzyme at a low-substrate concentration. With the amount of enzyme exceeding the amount of substrate, the reaction rate steadily increases as more substrate is added.

Active site

water free cavity, where the substrate interacts with particular charged amino acid residues

Constitutive enzymes

• Enzymes that are always present and perform some metabolic functions

Inducible enzymes

• Enzymes that are not always present but are produced in response to stimulus