Sulphur of cystein are not used/ utilized in body for the following process/product:
Ans: C (Introduction of .....) 285-86;Lippincott 6th/263-68; Shinde 7th/471 - 73.578; Vasudevan 5th/l 91; Satyanarayan 3rd/361]"The H2S derived from the cysteine may be oxidized to sulfites & thiosulfates & further oxidized to sulfate '- Vasudei'an 5th/l 93"Two molecules of cysteine are joined together by S-S bond to form one molecule of cystine (disulphide bond)"- Shinde 7th/473DEGRADATION OF CYSTEINE Vasudevan Sth/191Transamination: Cysteine transaminates to form beta me rcapto pyruvic acid & finally pyruvate. The beta mercapto pyruvate can transfer S to CN to form thiocynate (SCN)The sulphur mav be removed either as H.25 or elemental sulphor or as sulfiteCysteine on decarboxylation gives beta mercapto ethanol- amine . This is used for synthesis of co-enzyme A"Formation of cysteine is by using the carbon skeleton contributed by serine & sulphur originating from methionine"- Vasudevan 5th/191"Sulphur containing amino acids in body are- methionine, cysteine & cystine. Other source of sulphur in body are sulphur containing amino acids: thiamine, lipoic acid & biotin"- Shinde 7th/471"Cystine; This amino acid is reduced to cysteine, using NADH + H' as a reductant. Cysteine undergoes desulfuration to yield pyruvate.[Note; The sulfate released can be used to synthesize 3'-phosphoadenosine-5r-phosphosulfate (PAPS), an activated sulfur donor to a variety of acceptorsj.Cysteine can be oxidized to its disulfide derivative, cystine"- Lippincott 6th/263
Help in conversion of cyanide to thiocynate
Thiosulphate formation
Introduction of sulphur atom in methionine
Disulfide bond formation b/w two adjacent peptide
Miscellaneous (Structure & Function of Proteins)