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