REDUCING ENZYME CONFORMATIONAL FLEXIBILITY BY MULTIPOINT COVALENT IMMOBILIZATION

A thermostable esterase was immobilised to glyoxyl-agarose under conditions designed to generate ''limited-linkage'' and ''multi-point'' covalent derivatives. The multi-point derivative was 830-fold more thermostable than the Limited-linkage derivative and retained more activity in the presence of sodium chloride and organic solvents. Medium chain (C8) aliphatic p-nitrophenyl ester substrates, which inactivate the soluble enzyme, were shown to be more readily hydrolysed. Together these data support the contention that multi-point covalent immobilisation results in a more rigid, less conformationally flexible protein structure.