INFLUENCE OF THE NATURE OF MODIFIER IN THE ENZYMATIC-ACTIVITY OF CHEMICAL MODIFIED SEMIPURIFIED LIPASE FROM CANDIDA-RUGOSA

Semipurified lipase of Candida rugosa (CRSL) was subjected to chemical modification, and the activities of the modified lipase, in hydrolysi s and esterification reactions, were examined. The esterification reac tions were carried out in the absence and presence of isooctane. When the enzyme was modified with polyethylene glycol (PEG), two methodolog ies were studied. The activation of PEG with p-NO2-phenylchloroformate gives better biocatalysts than those obtained with cyanuric chloride- PEG. The chemical modification with PEG increases the stability of pur e lipases in isooctane at 50 degrees C (extreme conditions). The chemi cally modified enzymes are useful for biotransformations in organic so lvents. In addition the nitration of tyrosines with tetranitromethane was also studied. (C) 1997 John Wiley & Sons, Inc.