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IRRADIATION OF INDUSTRIAL ENZYME PREPARATIONS I. CHARACTERIZATION OF FUNGAL AND BACTERIAL PROTEASES BY THIN‐LAYER ISOELECTRIC FOCUSING AND GEL FILTRATION
Author(s) -
DELINCEE HENRY
Publication year - 1978
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1978.tb00603.x
Subject(s) - isoelectric point , proteases , size exclusion chromatography , protease , chromatography , isoelectric focusing , chemistry , enzyme , biochemistry
The treatment of industrial enzyme preparations with ionizing radiations to reduce microbial contamination demands a thorough characterization of these enzymes in order to identify possible changes in their physico‐chemical properties. Fungal and bacterial proteases were fractionated with respect to their charge and size properties by means of thin‐layer isoelectric focusing and gel filtration, respectively. Both enzymes were highly heterogeneous on focusing: the protease from A. oryzae consists of at least fifteen multiple forms mainly in the acid pH range, the predominant component having an isoelectric point of 5. 7, whereas the protease from B. subtilis exhibited about 10 components in the alkaline pH range 7–10 with the main zone at pH 8. 2. The molecular weights of the main enzyme fractions separated by gel filtration were estimated to be 22,000 for the fungal and 16,000 for the bacterial protease. Irradiation treatment with doses up to 1 Mrad of 60 Co‐γ‐rays and doses much in excess (up to 20 Mrad) revealed no changes in the charge and size properties of these proteases, thereby confirming the attraction of the irradiation process for the reduction of microbial contamination of industrial enzyme preparations.