Determination of the rates of formation and hydrolysis of the Schiff bases formed by 5′-deoxypyridoxal and poly-l-lysine

✍ Scribed by M.Angeles García del Vado; Gerardo R. Echevarría; JoséG.Santos Blanco; Francisco García Blanco

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 529 KB
• Volume: 118
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(96)00133-1

✦ Synopsis

The kinetics of the reaction between 5'-deoxypyridoxal (DPL) and poly+lysine in aqueous solutions at a variable pH and a constant ionic strength of 0.1 M was studied spectrophotometrically.

The rate constants of formation and hydrolysis of the resulting Schiff base and its stability constant at a variable pH were also determined. A comparison of the formation rate constant for the Schiff base with those for the models of pyridoxal S-phosphate (PLP) with poly-L-lysine and DPL with n-hexylamine revealed the effect of both the phosphate group of PLP and of the polypeptide chain on intramolecular catalysis in the dehydration of the intermediate carbinolamine formed. The effects of the polypeptide and the phosphate group on the hydrolysis of the Schiff base and hence on the base stability are also demonstrated.