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Properties of β‐galactosidase of Lactobacillus kefiranofaciens K‐1 isolated from kefir grains
Author(s) -
Itoh K.,
Toba T.,
Itoh T.,
Adachi S.
Publication year - 1992
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.1992.tb00771.x
Subject(s) - kefir , lactobacillus , bacteria , biology , lactobacillaceae , food science , microbiology and biotechnology , chemistry , lactic acid , fermentation , genetics
β‐Galactosidase from Lactobacillus kefiranofaciens K‐1 was isolated and characterized. Optimal temperature and pH for the enzyme reaction were 50 ° C and pH 6.5, respectively. Molecular weight was estimated to be approximately 311000. Glucose and galactose inhibited the activity, but the inhibition by galactose was rather weaker than observed in other β‐galactosidases. MnCl 2 and MgCl 2 had no effect on the activity. FeSO 4 , AgNO 3 and HgCl 2 acted as the inhibitor. β‐Mercaptoethanol and L‐cysteine activated the enzyme, while iodoacetamide inhibited the activity. The K m values were 4.92 mmol/1 for ONPG and 1.27 mmol/1 for lactose.