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Assay Conditions Effect on β‐Galactosidase Activity from Kluyveromyces lactis
Author(s) -
PIVARNIK LORI F.,
RAND ARTHUR G.
Publication year - 1992
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1992.tb14346.x
Subject(s) - kluyveromyces lactis , lactose , potassium , chemistry , kluyveromyces , substrate (aquarium) , phosphate , potassium phosphate , chromatography , lactase , food science , phosphate buffered saline , biochemistry , yeast , biology , saccharomyces cerevisiae , ecology , organic chemistry
β‐galactosidase, derived from Kluyveromyces lactis was assayed for activity using lactose, buffered at pH 6.5 with 0.02M potassium phosphate, and reconstituted nonfat dry milk (NFDM) substrates. Variations in buffer strength, potassium ion concentration and water quality were evaluated. Assay under similar conditions using NFDM and buffered lactose resulted in 4.3 and 6.6 units of activity, respectively. Increasing buffer strength to 0.1M potassium phosphate resulted in a 20% decrease in lactase activity units. Addition of potassium ions, as 0.5M KC1, in the enzyme preparation resulted in an increase in observed activity using both assay systems with a greater impact (160% increase) using NFDM vs buffered lactose (120% increase) as the substrate.