University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

496

Pages:

5
Author:

Sheha A.

Urea Cycle The urea cycle is a cycle of biochemical reactions occurring in liver. It converts ammonia (NH3) that is produced as a result of protein metabolism. Liver is the filter of the body and thus excretion of urea occurs in liver. Reactions in the Urea Cycle Synthesis of carbamoyl phosphate Formation of citrulline Cleavage of argininosuccinate Cleavage of arginine Synthesis of carbamoyl phosphate Ammonia enters the urea cycle after condensation with bicarbonate to form carbamoyl phosphate. 5. Cleavage of Argininosuccinate The reaction is catalyzed by argininosuccinase. Argininosuccinate cleaves to form arginine and fumarate. The reaction involves the cleavage of the bond between the amino group of arginine and the carbon group of fumarate. Argininosuccinate is cleaved into arginine and fumarate. 4. Cleavage of Arginine The reaction is catalyzed by arginase. Arginine is cleaved into urea and ornithine. The reaction involves the hydrolysis of the guanidino group of arginine. The mitochondria can join the pool of citric acid cycle intermediates. Cleavage of arginine. In last reaction of urea cycle, arginase cleaves arginine to yield urea and ornithine. Ornithine is transported into the mitochondria and initiates and regulates the another round of urea cycle.