Inactivation of carboxypeptidase A and trypsin by UV-visible light

In the present work, the effect of UV-visible irradiation on the activity of carboxypeptidase A, and trypsin enzymes is shown. The irradiation of the above-mentioned enzymes inhibits their activity. in such a way that sufficiently high irradiation times annul their catalytic action. For carboxypeptidase A a total inactivation after 20 min of irradiation is observed, while trypsin is inactivated completely after 12 min of irradiation. Fitting the data to the Lineweaver-Burk graphs shows that, in the case of CPA enzyme, the inhibition caused by irradiation is similar to that of uncompetitive type. For trypsin, the irradiation acts similarly to a mixed inhibition-type. Industrial relevance: UV irradiation is a technology used in food treatment, since it has been shown to be effective in the destruction of microorganisms. It can also be applied in the sterilization of enzymatic preparations used in the food industry, but it can have harmful effects, since it can go so far as to inactivate some of the enzymes. In some cases it interests to inactivate enzymes, and it is for it that this treatment type can be effective. In other cases it interests that the enzymes remain active. This way, it will be necessary to avoid that they are exposed to the light. (C) 2009 Elsevier Ltd. All rights reserved.