Lecture 49 Flashcards
_____ is the precursor for Cytosine, Thymine, and Uracil.
OROTIC ACID
_____ phosphate synthetase II is specific to Pyrimidine biosynth and is located in the _____, whereas _____ phosphate synthetase I is specific to the _____ cycle and is located in the ____ _____.
CARBAMOYL phosphate synthetase II is specific to Pyrimidine synthesis and is located in the CYTOSOL, whereas CARBAMOYL phosphate synthetase I is specific to the UREA cycle and is located in the MITOCHONDRIAL MATRIX.
_____ is a carbon source and _____ is an amino source for Carbamoyl phosphate for pyrimidine synthesis. It is also an amino source in ____ synthesis.
HCO3 is a carbon source and GLUTAMINE is an amino source for Carbamoyl phosphate for pyrimidine synthesis. It is also an amino source for PURINE synthesis.
Carbamoyl Phosphate synthetase is inhibited by _____ and activated by _____ and _____.
It is inhibited by UTP, and activated by ATP and PRPP.
Pyrimidine synthesis differs from Purine synthesis in that Pyrimidine synth begins with _____ formation followed by link to _____. This is opposite in Purine synth.
Pyrimidine synthesis begins with RING formation followed by link to RIBOSE.
CAD is a single polypeptide with 3 domains, each with a different catalytic activity, including ______ ______ ______ (C), ______ ______(A), and ______ (D)
Including Carbamoyl Phosphate Synthetase, Aspartate Transcarbamylase, and Dihydroorotase.
The second enzyme complex involved in pyrimidine synth is _____ synthase, which is composed of orotate phosphoribosyl transferase that adds _____ to Orotate forming OMP and then OMP decarboxylase forming ____ from OMP.
The second enzyme complex is UMP-synthase, which is composed of orotate phosphoribosyl transferase that adds PRPP to Orotate forming OMP and then OMP decarboxylase forming UMP from OMP.
Low UMP synthase activity (in either one of the 2 enzyme components) leads to _____ aciduria, showing symptoms such as _____ anemia and abnormal growth. It can be treated with a _____-rich diet.
It leads to OROTIC aciduria, showing symptoms such as MEGALOBLASTIC anemia and abnormal growth. It can be treated with a URIDINE-rich diet.
____ is the AA that is unique to purine synthesis; both Glutamine and Apartate are shared.
GLYCINE is unique.
____ synthetase forms Cytosine from Uracil (UTP) and requires _____ and Glutamine.
CTP synthase forms Cytosine from Uracil and requires ATP and Glutamine.
Pyrimidine degradation products are ____, so there are no equivalent disorders as in Purine degradation, which can lead to Gout.
They are SOLUBLE.
______ ______ and ______ ______ are the 2 enzymes required to convert RNA to DNA.
THYMIDYLATE SYNTHETASE and RIBONUCLEOTIDE REDUCTASE
Ribonucleotide Reductase reduces the C at the _____ position, forming a C-H bond instead of the C-OH that was there originally.
It reduces the C at the 2’ position.
_____ is a general inhibitor of Ribonucleotide reductase and _____ is a general activator.
dATP is a general inhibitor, and ATP is a general activator.
Ribonucleotide reductase only recognizes the _____phosphate forms of the Nucleotides.
It only recognizes the DIphosphate forms.
