Purification and properties of a keratinolytic metalloprotease from Microbacterium sp.
OBJECTIVE
This study was developed to purify and to characterize a keratinolytic protease from the bacterium Microbacterium sp. strain kr10.


RESULTS
Enzyme purification was carried out by sequential liquid chromatography on Sephadex G-100 and Q-Sepharose columns. The purification was about 255-fold, with a yield of 34%, as determined with azocasein as substrate. The molecular weight of the enzyme was estimated as 42,000 Da by SDS-PAGE. The enzyme had pH and temperature optima of 7.5 and 50 degrees C respectively. This keratinase was inhibited by EDTA and 1,10-phenanthroline, and analysis of metal content indicates that Zn(2+) and Mg(2+) are present. A 2(2) factorial design was developed to investigate the effect of keratinase and mercaptoacetate concentration on feather keratinolysis. Statistical analysis showed that both variables have a significant effect on hydrolysis of keratin.


CONCLUSIONS
A new keratinase produced by Microbacterium sp. was purified and characterized.


CONCLUSIONS
This keratinolytic enzyme offers an interesting potential for the hydrolysis of keratin wastes to be used as feed supplement or bioconversion to added-value products.
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Laboratório de Bioquímica e Microbiologia Aplicada, Departamento de Ciência de Alimentos, ICTA, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Brandelli
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D000818:Animals; D002853:Chromatography, Liquid; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005241:Feathers / Q000378:metabolism / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007633:Keratins / Q000378:metabolism; D008274:Magnesium / Q000032:analysis; D008970:Molecular Weight; D009161:Mycobacterium / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010618:Phenanthrolines / Q000494:pharmacology; D013696:Temperature; D013864:Thioglycolates / Q000494:pharmacology; D015032:Zinc / Q000032:analysis
D004791:Enzyme Inhibitors; D010618:Phenanthrolines; D013864:Thioglycolates; D007633:Keratins; C017487:2-mercaptoacetate; D004492:Edetic Acid; D010447:Peptide Hydrolases; C035855:keratinase; D008274:Magnesium; D015032:Zinc; C025205:1,10-phenanthroline