Nucleotide Metabolism (LM 12.1) Flashcards
why are nucleotides important in metabolism?
- they’re activated precursors of DNA and RNA
- nucleotide derivatives are activated intermediates in many biosynthetic pathways like UDP-glucose, CDP-diacylglycerol and S-adenosyl methionine
- ATP is the universal currency of energy in cells, GTP plays a role in certain cases like protein synthesis
- adenine nucleotides are components of 3 major coenzymes: NAD+ FAD and CoA
- nucleotides are metabolic regulators: cAMP
why do people study nucleotide metabolism?
genetic disorders of nucleotide metabolism are serious
inhibitors of nucleotide synthesis arrest cell growth and sometimes we want to do this like in cancer!
rapidly growing cells require high rates of nucleotide synthesis for RNA and DNA - some cancer cells are more sensitive to these inhibitors than normal cells
lots of antibiotics inhibit nucleotide synthesis in microbes
what are the 3 kinds of bonds in nucleotides?
- acid anhydride: bonds between adjacent phosphates
- phosphate monoester: between hydroxyl on the sugar and the phosphate group
- N-glycosidic: between base and sugar
what is the first purine nucleotide synthesized in the de novo pathway?
IMP
which enzymes in the purine biosynthetic pathway are regulated by feedback inhibition?
PRPP synthetase and PRPP glutamyl amidotransferase
what’s the committed step in purine synthesis?
PRPP –> phosphoribosylamine via PRPP glutamyl amidotransferase because phosphoribosylamine is only an intermediate in purine synthesis
what causes gout?
purine catabolism disorders!!
gout = hyperuricemia
they can also cause inherited immunodeficiencies
what is ADA?
adenosine deaminase
used in purine catabolism to catalyze adenosine –> inosine
what are the physiological causes of gout?
- overproduction of uric acid
2. decreased elimination of uric acid
