Moroz A R, Kondakov V I, Stepuro I I, Iaroshevich N A
Biokhimiia. 1987 Apr;52(4):550-61.
Pyridoxal-5-phosphate (in a lesser degree, pyridoxal) interacts with both non-protonated and protonated exposed epsilon-amino groups of lysine residues and with alpha-amino groups in human serum albumin and pancreatic ribonuclease A. The reaction of Schiff base formation proceeds within a wide pH range--from 3.0 to 12.0. At a great pyridoxal-5-phosphate excess in ribonuclease A in neutral or slightly acidic aqueous media all the ten epsilon-amino groups of lysine residues and the alpha-amino groups of Lys-1 become modified. The formation of aldimine bonds of pyridoxal-5-phosphate with protonated amino groups in acidic media is determined by ionization of its phenol hydroxyl and phosphate residues. Acetaldehyde, propionic aldehyde and pyridine aldehyde interact only with non-protonated amino groups of the proteins. The equilibrium constants of pyridoxal-5-phosphate and other aldehydes binding to proteins and amino acids were determined. The rate constants of Schiff base formation for pyridoxal-5-phosphates with some amino acids and primary sites of proteins for direct and reverse reactions were calculated.
磷酸吡哆醛（程度稍低的还有吡哆醛）可与赖氨酸残基未质子化和质子化的暴露ε-氨基以及人血清白蛋白和胰腺核糖核酸酶A中的α-氨基相互作用。席夫碱形成反应在较宽的pH范围内进行，即从3.0至12.0。在中性或微酸性水性介质中，当核糖核酸酶A中磷酸吡哆醛大量过量时，赖氨酸残基的所有十个ε-氨基以及Lys-1的α-氨基都会被修饰。在酸性介质中，磷酸吡哆醛与质子化氨基形成醛亚胺键取决于其酚羟基和磷酸残基的电离。乙醛、丙醛和吡啶醛仅与蛋白质的未质子化氨基相互作用。测定了磷酸吡哆醛和其他醛与蛋白质及氨基酸结合的平衡常数。计算了磷酸吡哆醛与一些氨基酸以及蛋白质主要位点形成席夫碱的正向和逆向反应的速率常数。
