Characterization of human triosephosphate isomerase S-nitrosylation.
Triosephosphate isomerase (TPI), the glycolytic enzyme that catalyzes the isomerization of dihydroxyacetone phosphate (DHAP) to glyceraldehyde-3-phosphate (G3P), has been frequently identified as a target of S-nitrosylation by proteomic studies. However, the effect of S-nitrosylation on its activity has only been explored in plants and algae. Here, we describe the in vitro S-nitrosylation of human TPI (hTPI), and the effect of the modification on its enzymatic parameters. NO-incorporation into the enzyme cysteine residues occurred by a time-dependent S-transnitrosylation from both, S-nitrosocysteine (CySNO) and S-nitrosoglutathione (GSNO), with CySNO being the more efficient NO-donor. Both X-ray crystal structure and mass spectrometry analyses showed that only Cys217 was S-nitrosylated. hTPI S-nitrosylation produced a 30% inhibition of the Vmax of the DHAP conversion to G3P, without affecting the Km for DHAP. This is the first study describing features of human TPI S-nitrosylation.
['Romero|Jorge Miguel|JM|', 'Carrizo|María Elena|ME|', 'Curtino|Juan Agustín|JA|']
D006801:Humans D013058:Mass Spectrometry D009569:Nitric Oxide D009603:Nitroso Compounds D014305:Triose-Phosphate Isomerase
Triosephosphate isomerase S-nitrosylation S-nitrosocysteine S-nitrosoglutathione Nitric oxide