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) 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.
D002850:Chromatography, Gel; D003035:Cobalt / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D005696:Galactosidases / Q000032:analysis* / Q000037:antagonists & inhibitors; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000494:pharmacology; D008628:Mercury / Q000494:pharmacology; D014166:Transferases / Q000032:analysis; D014244:Trichomonas / Q000201:enzymology*
D003035:Cobalt; D008345:Manganese; D004492:Edetic Acid; D014166:Transferases; D005696:Galactosidases; D008628:Mercury