Cell-wall-bound proteinase of Lactobacillus delbrueckii subsp. lactis ACA-DC 178: characterization and specificity for beta-casein.
Lactobacillus delbrueckii subsp. lactis ACA-DC 178, which was isolated from Greek Kasseri cheese, produces a cell-wall-bound proteinase. The proteinase was removed from the cell envelope by washing the cells with a Ca2+-free buffer. The crude proteinase extract shows its highest activity at pH 6.0 and 40 degrees C. It is inhibited by phenylmethylsulfonyl fluoride, showing that the enzyme is a serine-type proteinase. Considering the substrate specificity, the enzyme is similar to the lactococcal PI-type proteinases, since it hydrolyzes beta-casein mainly and alpha- and kappa-caseins to a much lesser extent. The cell-wall-bound proteinase from L. delbrueckii subsp. lactis ACA-DC 178 liberates four main peptides from beta-casein, which have been identified.
Tsakalidou
E
E
Laboratory of Dairy Research, Department of Food Science and Technology, Agricultural University of Athens, 118 55 Athens, Greece.
Anastasiou
R
R
Vandenberghe
I
I
van Beeumen
J
J
Kalantzopoulos
G
G
D000595:Amino Acid Sequence; D002364:Caseins / Q000737:chemistry / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology; D002611:Cheese / Q000382:microbiology; D010450:Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000201:enzymology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
D002364:Caseins; D010446:Peptide Fragments; D010450:Endopeptidases