Cystine decarboxylase

The aerobic metabolism of cystine-3 5S by chicken embryo, investigated166 both in vivo and in vitro, resulted in the formation of cystinedisulphoxide-35S (in vitro only), [35S] cystinesulphinic acid, [35S] cysteic acid, [35S]taurine and sulphate-35S. Hypotaurine has been detected neither in vivo nor in vitro. This indicates that, contrary to what had been observed in mammalian liver, hypotaurine is not the precursor of taurine in chicken embryo (equation 86). The enzyme decarboxylase, which effectively decarboxylates [35S]cysteic acid, does not act on cysteinesulphinic acid. Sulphate-35S may be produced also by the desulphination of cysteinesulphinic acid (equation 87) or from some other... 

Oxidation of Cystine, Cystine has been reported to initiate a series of reactions in which the S—S bond remains intact. An oxidation product is cystine disulfoxide, RSOSOR. This compound can yield both cysteine and sulfate in the intact rat, but most of it is converted to taurine. Both carboxyl groups of cystine disulfoxide are removed by a decarboxylase different from cysteic decarboxylase. Oxidation and hydrolysis of the decarboxylation product would yield two equivalents of taurine, but the individual steps of this conversion have not been isolated. 

Creatine biosynthesis defects Lysosomal cystine transport def., infantile Lysosomal cystine transport def, adolescent Hyperoxaluria type 1 Malonyl-CoA decarboxylase def Lysosomal cystine transport def, infantile Lysosomal cystine transport def, adolescent... 

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