INFLUENCE OF MILK-PROTEINS ON THE THERMOSTABILITY OF THE LIPASE FROM PSEUDOMONAS-FLUORESCENS-33

The effects of some milk proteins on the thermostability of the lipase from Pseudomonas fluorescens 33 were investigated. All purified milk protein fractions except kappa-casein that dissolved in phosphate buff er were effective for thermostabilization of the lipase. Thermal behav ior of the lipase containing beta-lactoglobulin was so specific that, after heating at 80 to 90-degrees-C, activity remained high and was co mparable with that of unheated treatment. The thermostability of the l ipase containing whey proteins in synthetic salts solution was extensi vely lowered, but that containing casein micelles retained 50% of orig inal activity after heat treatment at 80-degrees-C for 10 min. Low tem perature inactivation of the lipase was influenced by concomitant milk proteins.