Nitrosation of tryptophan residue(s) in serum albumin and model dipeptides. Biochemical characterization and bioactivity
| Autor: | Y Y, Zhang, A M, Xu, M, Nomen, M, Walsh, J F, Keaney, J, Loscalzo |
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| Rok vydání: | 1996 |
| Předmět: |
Male
Photolysis Platelet Aggregation Sodium Nitrite Protein Conformation Circular Dichroism Vasodilator Agents Tryptophan Serum Albumin Bovine Dipeptides Glutathione Muscle Smooth Vascular Structure-Activity Relationship Spectrophotometry Luminescent Measurements Animals Humans Cattle Cysteine Rabbits Sulfhydryl Compounds Aorta Platelet Aggregation Inhibitors Nitroso Compounds |
| Zdroj: | The Journal of biological chemistry. 271(24) |
| ISSN: | 0021-9258 |
| Popis: | Nitrosation of bovine serum albumin with acidified NaNO2 was compared to that of carboxymethyl-bovine serum albumin in which the thiol group is covalently blocked. Differential ultraviolet-visible (UV-Vis) spectroscopy and a modified Saville assay indicated that a non-cysteine residue(s) in carboxymethyl-bovine serum albumin was nitrosated. The nitrosated carboxymethyl-bovine serum albumin exhibited similar vasorelaxation activity as that observed with nitrosated bovine serum albumin. Identification of the nitrosated non-cysteine residue(s) was studied using 16 model dipeptides, each of which contained a glycyl residue and a variable residue. Using photolysis-chemiluminescence analysis, modified Saville assay, differential UV-Vis spectroscopy, and bioassays, L-glycyl-L-tryptophan (Gly-Trp) was found to be the only dipeptide that underwent significant nitrosation under these conditions. Liquid chromatography-UV-Vis spectroscopy-mass spectrometry showed that the NO group was attached to the indole nitrogen of tryptophan. Nitrosated Gly-Trp exhibited dose-dependent vasorelaxation and platelet inhibiting activity with apparent EC50 values of 1.1 +/- 0. 3 and 3.5 +/- 0.9 microM, respectively. Because N-nitroso-Gly-Trp does not release NO radical via spontaneous homolytic N-NO bond fission nor freely diffuse through cellular membranes, the ability of this compound to induce NO.-like biological effects suggests the existence of a (membrane-associated) transnitrosation system that facilitates delivery of -NO to its specific biologic target(s). |
| Databáze: | OpenAIRE |
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