Characterization of extracellular beta-lactamases from penicillin G-resistant cells of Streptococcus thermophilus

1998-07-01
In this study, biochemical properties of two extracellular beta-lactamases produced by penicillin-resistant Streptococcus thermophilus cells were investigated. Both beta-lactamases showed specificity for penicillins but not for cephaloridins. The p-lactamases exhibited different affinities for penicillin G. The one with the higher molecular weight (F1) had a K(m) value of 3.44 mu M and a V(max), value of 8.33, mu mol/min/mg of protein, whereas the beta-lactamase with the lower molecular weight (FII) had a K(m) value of 4.76 mu M and a V(max) value of 3.13 mu mol/min/mg of protein. Both beta-lactamases were inhibited by iodine, copper sulfate, and iron sulfate but not by EDTA. The optimal pH ranged between 6 and 7. and the optimal temperatures were between 40 and 45 degrees C for both enzymes.
JOURNAL OF FOOD PROTECTION

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Citation Formats
L. Chirica, N. T. Güray, G. C. Gültekin, and F. Bozoglu, “Characterization of extracellular beta-lactamases from penicillin G-resistant cells of Streptococcus thermophilus,” JOURNAL OF FOOD PROTECTION, pp. 896–898, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48947.