[Solid-phase enzymatic reactions. V. Comparison of catalytic properties of subtilisin and alpha-chymotrypsin in the absence of a solvent].

Subtilisin Carlsberg (E.C. 3.4.21.14) catalyzes the hydrolysis of N-succinyl-L-phenylalanine p-nitroanilide in solid-state solvent-free hydrated protein-substrate mixtures. This process needs a certain critical degree of hydration of the protein molecule which is attained at the relative water vapour pressure (p/ps) above 0.49. The identical hydration dependency was found for the solid-state inactivation of subtilisin by phenylmethylsulphonylfluoride. Despite the fact that subtilisin and alpha-chymotrypsin belong to two different families of serine proteinases, the characteristics of their solid-state catalytic reactions are almost identical.