30 Questions
What is the product of oxidative deamination of glutamate?
Keto acids and ammonia
What is the substrate specificity of aminotransferases?
Each aminotransferase is specific for one or a few amino group donors
What is the role of NAD+ in the oxidative deamination of glutamate?
To act as a co-enzyme
What is the product of the reaction catalyzed by alanine aminotransferase?
Pyruvate and glutamate
What happens when there are elevated levels of aminotransferases in the plasma?
Liver damage is indicated
What is the function of aspartate aminotransferase in the urea cycle?
It is a source of nitrogen in the urea cycle
What is the direction of the reaction catalyzed by glutamate dehydrogenase (GDH) dependent on?
The relative concentrations of glutamate, α-ketoglutarate, and ammonia
What is the coenzyme required for the activity of aminotransferases?
Pyridoxal phosphate
What is the reaction where glutamate is converted into α-ketoglutarate and ammonia?
Oxidative deamination
What is the co-enzyme required for the reductive amination reaction?
NADPH
What is the result of the transfer of the amino group of an amino acid to the pyridoxal part of the coenzyme?
Pyridoxamine phosphate
What is the type of bond formed between pyridoxal phosphate and the specific lysine amino acid at the active site of the enzyme?
Covalent bond
What is the first step in the degradation of absorbed dietary amino acids?
Removal of α-amino group
What is the product of transamination?
Glutamate and α-keto acid
Where does transamination primarily occur?
Liver
Which enzyme catalyzes transamination?
Aminotransferase
Which amino acids do not participate in transamination?
Lysine and Threonine
What is the result of oxidative deamination?
Ammonia
What is the primary purpose of the glucose-alanine cycle?
To synthesize glucose from pyruvate
Where does the formation of citrulline occur?
Mitochondria
What is the role of ALT in the glucose-alanine cycle?
To transaminate pyruvate to form alanine
What is the result of the reaction between ammonium ions and CO2 in the urea cycle?
Formation of carbamoyl phosphate
Where does the synthesis of argininosuccinate occur?
Cytosol
What is the purpose of the ornithine translocase?
To transport citrulline from the mitochondria to the cytosol
What is the total number of ATP molecules consumed in the formation of urea?
3
What is the product of the cleavage of argininosuccinate?
Arginine and fumarate
Where is arginase, the enzyme that cleaves arginine, mostly found?
Liver
What is the rate-limiting enzyme in the urea cycle?
Carbamoyl phosphate synthetase I (CPS-I)
What is the activator of CPS-I?
N-Acetylglutamate (NAG)
What is synthesized from glutamate and acetyl CoA by N-acetylglutamate synthase?
N-Acetylglutamate (NAG)
Learn about the two-step process of amino acid degradation, including the removal of the α-amino group and the breakdown of the carbon skeleton. Understand transamination, oxidative deamination, and the role of glutamate in this process.
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