数据之源，洞见之始

Metabolite Card

Note

The reactive species in the phosphofructokinase modulation system could be considered thiocysteine (R-S-S-) or cystine trisulfide (R-S-S-S-R) produced from cystine in the presence of gamma-Cystathionase (CST, EC 4.4.1.1). The desulfuration reaction of cystine in vivo produces thiocysteine containing a bound sulfur atom. Persulfide generated from L-cysteine inactivates tyrosine aminotransferase. Thiocysteine is the reactive (unstable) intermediate of thiocystine which functions as a persulfide in transferring its sulfane sulfur to thiophilic acceptors. Thiocystine conversion to unstable thiocysteine is accelerated by sulfhydryl compounds, or reagents that cleave sulfur-sulfur bonds to yield sulfhydryl groups. Thiocystine is proposed as the storage form of sulfane sulfur in biological systems. Liver cytosols contain factors that produce an inhibitor of tyrosine aminotransferase in 3 steps: initial oxidation of cysteine to form cystine; desulfurization of cystine catalyzed by cystathionase to form the persulfide, thiocysteine; and reaction of thiocysteine (or products of its decomposition) with proteins to form protein-bound sulfane. (PMID: 2903161, 454618, 7287665).