Purines and Pyrimidines Synthesis
Nucleotide Nitrogenous Bases What are the major pyrimidine bases?
Cytosine, Uracil, and Thymine (CUT the PY)
Nucleotide Pentoses Which kind of pentose is found in RNA?
D-ribose
De Novo Purine Nucleotide Synthesis Synthesis begins with ______
PRPP (5-Phosphoribosyl 1-pyrophosphate)
Two Pathways Lead to Nucleotides (De novo Pathways) Glu provides most _____ groups
amino
Nucleotide Synthesis Regulation Overview Tight regulation is needed to maintain balanced supplies of ______ ______ resources and ______ products
amino acid, nucleotide
Pyrimidine Nucleotide Synthesis _____ _____: catalyzes the first committed step and is highly regulated in ______
aspartate transcarbamoylase, bacteria
Pyrimidine Nucleotide Synthesis _____ and _____ _____ provide the atoms for the ring structure in pyrimidines
aspartate, carbamoyl phosphate
Two Pathways Lead to Nucleotides (De novo Pathways) _____ are synthesized while attached to ribose
bases
Nucleotides Nucleotides and Nucleic Acids have characteristic ______ and ______
bases, pentoses
Nucleotides Structural components of an array of enzyme _______ and metabolic ______
cofactors, intermediates
Pyrimidine Nucleotide Synthesis _____ _____ catalyzes the formation of CTP from UTP by way of an acyl phosphate intermediate. This reaction requires ATP
cytidylate synthetase
Nucleotides _____: structural units of DNA, also called deoxyribonucleoside 5'-monophosphates, deoxynucleotides, and deoxynucleoside triphosphates
deoxyribonucleotides
Nucleoside Kinases Nucleoside ______ kinases: convert nucleoside diphosphates to triphosphates
diphosphate (where A is the phosphate acceptor and D is the donor)
Nucleotides with Phosphate Groups in Different Positions Ribonucleoside 3'-monophosphates: ______ ______ of ______ _____
end products, RNA hydrolysis
Nucleotides Nucleotides are _____ currency in ______ transaction
energy, metabolic
Nucleotide Bonds The phosphate is ______ to the 5' carbon
esterified
Nucleotide Synthesis Regulation Overview Purine Nucleotide Biosynthesis is regulated by ______ inhibition
feedback
De Novo Purine Nucleotide Synthesis In the first committed step, an amino group donated by _____ is attached at C-1 of ______ to form ______
glutamine, PRPP, 5-phosphoribosylamine
De Novo Purine Nucleotide Synthesis In the second step, three atoms are added from ______. This reaction requires _____
glycine, ATP
Nucleoside Monophosphates are Converted to Nucleoside Triphosphates ADP is phosphorylated to ATP by _____ _____ or through ______ _____
glycolytic enzymes, oxidative phosphorylation
Nucleotides Essential chemical links in the response of cells to _______ and other extracellular ______
hormones, stimuli
Solubility of Nucleotides ______ and relatively ______ in pH 7.0 water (leads to stacking interactions, van der Waals and dipole-dipole forces)
hydrophobic, insoluble
De Novo Purine Nucleotide Synthesis In the eleventh step, a second ring closure occurs to form _____
inosinate (IMP)
Addition of the Amino Groups of AMP and GMP Conversion of ______ to ______ requires an amino group from aspartate and energy from GTP
inosinate (IMP), adenylate
De Novo Purine Nucleotide Synthesis Conversion of ______ to ______ requires an amino group from glutamine and energy from ATP
inosinate (IMP), guanylate
Nucleotides with Phosphate Groups in Different Positions Ribonucleoside 2',3'-cyclic monophosphates: _____ _____
isolatable intermediates
Nucleotide Synthesis Regulation Overview The metabolic flux through most of these pathways is far (more/less) than for carbohydrate or lipid biosynthetic pathways
less
Minor Purine and Pyrimidine Bases _______ forms are the most common in DNA
methylated
Nucleoside Kinases Nucleoside _____ kinases: Use ATP to form other nucleoside diphosphates
monophosphate
Nucleotides ______: the nucleotide molecule without a phosphate group
nucleoside
Nucleotides Nucleoside Monophosphates are converted to _____ _____
nucleoside triphosphates
Nucleotides _______ _______ occupy a central role in cellular metabolism, serving as an energy currency and as important regulatory signals
nucleoside triphosphates
Nucleoside and Nucleotide Nomenclature The suffix -ine is used for nucleotides or nucleosides?
nucleosides
Nucleoside and Nucleotide Nomenclature The suffix -ylate is used for nucleotides or nucleosides?
nucleotides
Two Pathways Lead to Nucleotides (De novo Pathways) Pyrimidine ring is synthesized as ______
orotate
Pyrimidine Nucleotide Synthesis ______ is decarboxylated to uridylate, which is phosphorylated to ______
orotidylate, UTP
Nucleotides In addition to a nitrogenous base, nucleotides contain a _____ and at least one ______ group
pentose, phosphate
De Novo Purine Nucleotide Synthesis Inosinate (IMP) is the first intermediate with a complete _____ _____
purine ring
Two Pathways Lead to Nucleotides (De novo Pathways) Gly is the precursor for ______
purines
Pyrimidine Nucleotide Synthesis Pyrimidine synthesis proceeds by first making the _____ _____ (in the form of _____)
pyrimidine ring, orotate
Nucleotides A nitrogenous base is comprised of either a _____ or a ______
pyrimidine, purine
Two Pathways Lead to Nucleotides (De novo Pathways) Asp is the precursor for ______
pyrimidines
Nucleotide Bonds An N-Beta-Glycosyl bond covalently joins the 1' carbon of the pentose to the N-1 of ______ and N-9 of ______
pyrimidines, purines
Purine Nucleotide Synthesis Regulation Four major feedback mechanisms cooperate in regulating: 1. The overall _____ of _____ _____ purine nucleotide synthesis 2. The relative rates of formation of _____ and ______
rate, de novo, AMP, GMP
Nucleotides ______: structural units of RNA, also called ribonucleoside 5'-monophosphates
ribonucleotides
Pyrimidine Nucleotide Synthesis In eukaryotes, the first three enzymes involved in pyrimidine nucleotide synthesis are part of a _____ _____ ______
single trifunctional protein (CAD)
Nucleotide Bonds Nucleotide bonds are formed by removal of the elements of ______
water
Pyrimidine Nucleotide Synthesis Aspartate transcarbamoylase is inhibited by what downstream product?
Cytidine 5'-triphosphate (CTP)
Nucleotide Bonds What kind of bond joins the 1' carbon of the pentose to the base?
N-Beta-Glycosyl bond
Nucleotide Synthesis Regulation Overview Quizlet fam: be familiar with feedback inhibition of purine nucleotide biosynthesis (image occlusion on anki)
.
Quizlet Fam be familiar with biosynthesis of AMP and GMP from IMP (image occlusion on quizlet)
.
Nucleotide Pentoses There are ___#___ kinds of pentoses
2
Nucleotide Pentoses Which kind of pentose is found in DNA?
2'-deoxy-d-ribose
Origin of Ring Atoms in Purines Adenine and guanine are synthesized as ______ and ______
AMP, GMP
Nucleoside Triphosphates _____ is the ultimate product of catabolic pathways, providing fuel for anabolic pathways
ATP
Pyrimidine Nucleotide Synthesis Aspartate Transcarbamoylase (ATCase) is accelerated by _____
ATP
Nucleotide Nitrogenous Bases What are the major purine bases?
Adenine and Guanine ("Pure As Gold)
Nucleotide Synthesis Pyrimidine nucleotides are made from _____, _____, and _____ _____
Aspartate, PRPP, Carbamoyl Phosphate
Nucleotide Pentoses Both D-Ribose and 2'-deoxy-d-ribose are in their ____-_____ form
Beta-furanose (closed five-membered ring)
Two Pathways Lead to Nucleotides Which type of pathway begins with metabolic precursors such as amino acids, ribose 5-phosphate, CO2, and NH3?
De novo pathways
Nucleotides Constituents of nucleic acids _______ ______ (DNA) and ______ ______ (RNA)
Deoxyribonucleic acid, ribonucleic acid
Pyrimidine Nucleotide Synthesis _______: catalyzes the removal of water from N-carbamoylaspartate to close the pyrimidine ring
Dihydroorotase
Nucleotide Synthesis Regulation Overview T/F: Most amino acids and nucleotides are stored in "nucleic pools" so they can be used as needed
False (most amino acids and nucleotides are not stored, but rather are synthesized as they are needed)
Pyrimidine Nucleotide Synthesis What is attached after pyrimidine ring formation?
Ribose 5-phosphate
Two Pathways Lead to Nucleotides Which type of pathway recycles the free bases and nucleosides released from nucleic acid breakdown?
Salvage Pathways
Nucleotide Nitrogenous Bases Which pyrimidine is only found in DNA?
Thymine
Nucleotide Nitrogenous Bases Which pyrimidine is only found in RNA?
Uracil
Solubility of Nucleotides Charged and more soluble at _____ or ______ pH values
acidic, alkaline
Nucleotides with Phosphate Groups in Different Positions What is the full name of cAMP?
adenosine 3',5'-cyclic monophosphate
Nucleoside Monophosphates are Converted to Nucleoside Triphosphates _____ _____: phosphorylates AMP to ADP
adenylate kinase