Penaeus vannamei protease activating mechanism of sulfhydryl reducing compounds.

For the very first time, protease enzyme from Penaeus vannamei was investigated for its activation with thiol reductant compounds. The mechanism by which sulfhydryl reductant compounds enhances the activity of P. vannamei protease still remains unclear. In this study, it was discovered that thiol-reactive compounds increase P. vannamei protease activity by a factor of about 4 with increasing V and decreasing Km parameters. Moreover, the reaction is an S2-type that does not require the initial binding of the thiol group of these compounds to the enzyme. Additionally, k increased appreciably with increasing concentration of sulfhydryl reductant compounds. The linearity of this plot indicates that k is unaffected by the addition of thiol compounds. Hence, the observed effect of thiol compounds on K seems to be due to an increase in k. These results suggest that the activation mechanism of P. vannamei protease almost certainly takes place by an S2 reaction mechanism.