A TRANSIENT NUCLEAR MAGNETIC RESONANCE STUDY OF KINETICS OF METHYL N-ACETYL-D-GLUCOSAMINIDE INHIBITION OF LYSOZYME

The kinetics of lysozyme inhibition by methyl N-acetyl-α- and -β-D-glucosaminide has been studied by transient nuclear magnetic resonance methods. The rates of formation and lifetimes of the lysozyme inhibitor complexes have been measured at 33° for the α anomer, and over the temperature range 11-61° for the β anomer. The rate constants at 33° are (k-1 sec-1, k1 m-1 sec-1) for α, 5.5 X 103, 1.4 X 105; for β, 4.5 X 103, 1.6 X 105. The activation parameters for the β anomer are (ΔH≠ kcal, ΔS≠ eu) for k-1, +4.4, - 27; for k1, -2.9, -44. These results suggest that the binding of monosaccharides to lysozyme is not a simple biomolecular process. The resonance frequency shift of the acetyl protons of the inhibitor upon binding to lysozyme at 33° is 0.65 ppm for the α anomer and 0.69 ppm for the β anomer. The equality of the shifts suggests that the anomers bind at the same site and in a similar configuration. © 1969, American Chemical Society. All rights reserved.