Observations on the Hydrolysis of p-Nitrophenyl Acylates by Purified Bovine Thrombin

Summary

The ability of purified bovine thrombin to catalyze the hydrolysis of p-nitrophenyl acetate and p-nitrophenyl butyrate has been studied. The butyrate derivative appears to be hydrolyzed more rapidly than the acetate derivative. An examination of the time course of hydrolysis of these compounds by thrombin shows an initial ‘‘burst” reaction followed by a slower ‘‘steady-state” reaction. The hydrolysis of p-nitrophenyl acylates by thrombin is inhibited by the presence of benzamidine as well as by prior reaction of thrombin with phenylmethylsulfonyl fluoride. It is suggested that bovine thrombin catalyzes the hydrolysis of p-nitrophenyl acylates and that the reaction proceeds via the formation of an acyl-enzyme intermediate.

• References

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