ENHANCEMENT OF DURABILITY OF CHYMOTRYPSIN THROUGH CROSS-LINKING WITH POLY(ALLYLAMINE)

α-Chymotrypsin (ChT) is covalently linked to various derivatives of poly(allylamine) (PAA) by using a carbodiimide as a coupling reagent. The PAA derivatives contain cationic, anionic, or hydrophobic microdomains. The ChTs linked to the PAA derivatives exhibit considerable stability against denaturing agents such as 0.5 m sodium dodecylsulfate or 4 m guanidinium chloride. This suggests multiple intramolecular cross-linking of ChT by the linear PAA derivatives. Stabilization of ChT by cross-linking with PAA derivatives is also reflected in much greater resistance of the PAA-bound ChTs to thermoinactivation. The multiple attachment of ChT to PAA derivatives does not significantly damage the active site as indicated by the reactivity of the modified ChTs at optimum pHs. © 1992.