All of the following are excreted in cystinuria, except:
Ans. b. LeucineRef: Harpers 30th Ed, Page No- 302Cystine, lysine, arginine, and ornithine are excreted in cystine-lysinuria (cystinuria), a defect in renal reabsorption of these amino acids.Apart from cystine calculi, cystinuria is benign. The mixed disulfide of 1-cysteine and 1-homocysteine excreted by cystinuric patients is more soluble than cystine and reduces formation of cystine calculi.Several metabolic defects result in vitamin B6-responsive or vitamin B6-unresponsive homocystinurias. These include a deficiency in the reaction catalyzed by cystathionine b-synthase;Serine+homocysteine-cystathionine +H2 O
Cystine
Leucine
Arginine
Ornithine
Proteins and Amino Acids