engleski

Stability of a new fungal keratinase

Keratinases are proteolytic enzymes which catalyze keratin hydrolisis. They have fifferent characteristics, because they could be produced by different microbial sources. Some keratinases are extracellular enzymes showing a high stability. The selcted non-pathogenic fungal strain was cultivated in submerged aerobic conditions. Crude keratinase was prepared by ultrafiltration of the culture filtrate and subsequent lyophilization of the retentate. Protein pattern of the crude enzyme was detected by SDS-PAGE electrophoresis. Enzyme activity was measured on human callus, using a modified method according to Takichi et al (1982), or hemoglobin as the enzyme substrates, using a method of Boehringer Manheim (1973). The influences of temperature, pH and type of buffer om the stability of crude keratinase was investigated. The half-life of the crude enzyme at the pH 7.5 and 40 C was 5 hours. Howewer, at 30 C the enzyme still retained nearly 20% of its activity after 48 hours of incubation. By measuring pH stability at room temperature the activity of the crude enzyme was still above 40 % after 48 hours in the pH range from 6.0 tp 8.0. The results obtained were compared with the characteristics of the commercial fungal keratinolytic enzyme proteinase K.

stability; keratinase

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