Thiolation of low-Mr phosphotyrosine protein phosphatase by thiol-disulfides |
| |
Authors: | Degl'Innocenti D Caselli A Rosati F Marzocchini R Manao G Camici G Ramponi G |
| |
Institution: | Dipartimento di Scienze Biochimiche, Università di Firenze, Italy. |
| |
Abstract: | Thiol-disulfides cause a time- and a concentration-dependent inactivation of the low-M(r) phosphotyrosine protein phosphatase (PTP). We demonstrated that six of eight enzyme cysteines have similar reactivity against 5,5'-dithiobis(nitrobenzoic acid): Their thiolation is accompanied by enzyme inactivation. The inactivation of the enzyme by glutathione disulfide also is accompanied by the thiolation of six cysteine residues. Inorganic phosphate, a competitive enzyme inhibitor, protects the enzyme from inactivation, indicating that the inactivation results from thiolation of the essential active-site cysteine of the enzyme. The inactivation is reversed by dithiothreitol. Although all PTPs have three-dimensional active-site structures very similar to each other and also have identical reaction mechanisms, the thiol group contained in the active site of low-M(r) PTP seems to have lower reactivity than that of other PTPs in the protein thiolation reaction. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|