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Use of a Milk Assay to Evaluate the Effects of Potassium on Commercial Yeast Lactases
Author(s) -
JACOBERPIVARNIK L. F.,
RAND A. G.
Publication year - 1984
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.1365-2621.1984.tb12438.x
Subject(s) - kluyveromyces lactis , lactase , potassium , chemistry , kluyveromyces , yeast , enzyme , food science , enzyme assay , substrate (aquarium) , hydrolysis , chromatography , biochemistry , saccharomyces cerevisiae , biology , ecology , organic chemistry
A reliable enzyme assay was developed that could routinely be used to accurately reflect lactase activity. The assay was performed with a nonfat dry milk substrate at 37°C. This procedure was then utilized to evaluate the effects of potassium ions as a stabilizer and activator on four yeast lactase enzymes. Low levels of potassium ions (K + ), incorporated as potassium chloride (KCl), increased enzyme units by 20% and 30% in two liquid lactases derived from Saccharomyces lactis . Levels as high as 9.4% KCl increased the activity of one liquid lactase as much as 160%. The K + activated and stabilized a powdered form of lactase isolated from Kluyveromyces fragilis . The activity of the fourth lactase tested, also derived from S. Zactis, was slightly enhanced.