Michaelis-Menten analysis of the hydrolyses of ONPG and PNPG by E. coli beta-galactosidase were performed from 5.5 to 45 degree C. Analysis of the T-dependence of KM and kcat reveals the thermodynamics for formation of the E / S complex and attainment of the galactosylation transition state, respectively. While the binding and transition state free energies are similar for each substrate, the enthalpic and entropic contributions are found to differ substantially.
Protein & Peptide Letters publishes short papers in all important aspects of protein and peptide research, including structural studies, recombinant expression, function, synthesis, enzymology, immunology, molecular modeling, drug design etc. Manuscripts must have a significant element of novelty, timeliness and urgency that merit rapid publication. Reports of crystallisation, and preliminary structure determinations of biologically important proteins are acceptable. Purely theoretical papers are also acceptable provided they provide new insight into the principles of protein/peptide structure and function.