Hydrolysis of poly(alkylene amidophosphate)s containing amino acid or peptide residues in the side groups. Kinetics and selectivity of hydrolysis.
Kinetics of hydrolysis of poly(alkylene amidophosphate)s with amino acids or dipeptides as the side groups was studied by 31P NMR at pH 1.5, 6.5, and 8.5. The direction of hydrolysis and the relative rate coefficients of breaking P-O bonds in the main chain and P-N bonds in the side groups depend strongly on the pH of the medium of hydrolysis. The P-N (amide) bond hydrolyzes much faster than the P-O (ester) bond in acidic and close to neutral conditions (negligible P-O hydrolysis), whereas above pH > or = 8.5 these differences are much smaller. For instance, for 4-Ala the rate coefficients of hydrolysis are equal (in H2O at 37 degrees C and pH 8.5) to 1.9 x 10(-8) s(-1) and 1.0 x 10(-9) s(-1) for the P-N and P-O bonds, respectively, quite different from the values found for the low molecular model 2 (0 and 1.4 x 10(-7) s(-1), respectively).
Baran
Jolanta
J
Center of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, Sienkiewicza 112.
Kaluzynski
Krzysztof
K
Szymanski
Ryszard
R
Penczek
Stanislaw
S
D000577:Amides / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics; D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*
D000577:Amides; D000596:Amino Acids; D010446:Peptide Fragments