[Possible mechanisms of mechanical enzyme inactivation]

The changes of trypsin structures during grinding have been studied. Destruction of covalent bonds inside the polypeptide chain and of disulfide bonds was discovered by ESR method. Grinding at room temperature is accompanied by hydrolysis of peptide bonds which is demonstrated by the formation of a great number of new N-terminal amino acids, determined by reaction with dansyl chloride. A change in trypsin tertiary structure resulting from grinding was shown by circular dichroism method. The analysis of the results obtained allows to conclude that the main cause of inactivation in the course of enzyme grinding are the conformational changes due to rupture and redistribution of weak bonds.