Enzymes of Trichomonas foetus. Separation and properties of two beta-galactosidases

The beta-galactosidase activity in extracts of Trichomonas foetus is separable into two fractions by gel filtration on Sephadex G-200. When o-nitrophenyl beta-d-galactoside is used as substrate the first fraction to be eluted, beta-galactosidase 1, has 50 times the activity (units per mg of protein)...

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Bibliographic Details
Published in:Biochemical journal Vol. 117; no. 4; p. 667
Main Authors: Harrap, G J, Watkins, W M
Format: Journal Article
Language:English
Published: England 01.05.1970
Subjects:
Chromatography, Gel
Cobalt - pharmacology
Edetic Acid - pharmacology
Galactosidases - analysis
Galactosidases - antagonists & inhibitors
Hydrogen-Ion Concentration
Manganese - pharmacology
Mercury - pharmacology
Transferases - analysis
Trichomonas - enzymology
ISSN:0264-6021
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Summary:The beta-galactosidase activity in extracts of Trichomonas foetus is separable into two fractions by gel filtration on Sephadex G-200. When o-nitrophenyl beta-d-galactoside is used as substrate the first fraction to be eluted, beta-galactosidase 1, has 50 times the activity (units per mg of protein) of the crude preparation. This fraction is activated by Mn(2+) and Co(2+) and inhibited by Hg(2+) and EDTA. In the presence of Mn(2+) the pH optimum for the hydrolysis of o-nitrophenyl beta-d-galactoside or lactose is 5.8-6.0. beta-Galactosidase 1 is an exoglycosidase that releases beta-linked galactose joined to aliphatic and various carbohydrate aglycones. Hydrolysis is prevented, however, by a substituent on either the subterminal sugar or the terminal non-reducing beta-galactosyl residue in an oligosaccharide. The second fraction, beta-galactosidase 2, is not activated by metal ions or inhibited by EDTA and has a broad pH optimum from 4.5 to 6.0.
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ISSN:0264-6021
DOI:10.1042/bj1170667