Amino Acid Catabolism and Anabolism

Which enzyme catalyzes the conversion of a-KG → Glutamate?

Glutamate Dehydrogenase

Which enzyme catalyzes the simultaneous conversion of glutamate → a-KG and an a-keto acid → a-amino acid?

Transanimase

Which enzyme catalyzes the conversion of Glutamate to Glutamine?

Glutamine synthetase

What is the rate limiting step for glutamine biosynthesis?

Glutamine synthetase

What enzyme converts Glutamine → glutamate?

Glutaminase

How is NH4 transported to the liver for the urea cycle?

by glutamine or by the glucose alanine cycle

Where does the first step of the urea cycle take place?

the mitochondria

Where does the second step of the urea cycle takes place?

the mitochondria

Where does the third step of the urea cycle takes place?

the cytosol

Where does the fourth step of the urea cycle take place?

the cytosol

Where does the final step of the urea cycle take place?

the cytosol

What is the first step of the urea cycle?

conversion of NH4+ → carbomyl phosphate

What enzyme catalyzes the conversion of NH4+ → carbomyl phosphate?

CPS 1

What is the rate limiting step of the urea cycle?

conversion of NH4+ → carbomyl phosphate

What is the rate limiting enzyme of the urea cycle?

CPS 1

What cofactor is required for CPS 1 activity?

N-aceytlglutamate

Under what conditions is N-acetylglutamate synthesized?

When proteins are abundant

Is N-acetylglutamate required for CPS 2 activity?

no

What is the second step of the urea cycle?

conversion of carbomyl phosphate → citrulline

What molecule is needed for the conversion of carbomyl phosphate → citrulline?

ornithine

What enzyme catalyzes the conversion of carbomyl phosphate → citrulline?

Ornithine transcarbamolyase

What is the third step of the urea cycle?

conversion of citrulline → argininiosuccinate

What amino acid is needed for the conversion of citrulline → argininiosuccinate?

Aspartate

What enzyme converts citrulline → argininiosuccinate?

argininosuccinate synthetase

What is the fourth step of the urea cycle?

conversion of argininosuccinate → arginine

What enzyme is responsible for the conversion of argininosuccinate → arginine?

arginino succinate

What is the final step of the urea cycle?

conversion of arginine → ornithine

What enzyme converts arginine → ornithine?

arginine

What is regenerated at the end of the urea cycle?

ornithine