PURIFICATION AND PROPERTIES OF PENICILLINASES FROM TWO STRAINS OF BACILLUS LICHENIFORMIS: A CHEMICAL, PHYSICOCHEMICAL AND PHYSIOLOGICAL COMPARISON.

摘要: Abstract 1. The penicillinases formed by penicillinase-constitutive mutant strains from two closely related varieties (749 and 6346) of Bacillus licheniformis have been isolated, characterized compared. They are chemically, physicochemically immunologically very similar, but differ enzymologically in absolute relative activity on, affinity for, different penicillins cephalosporins. 2. molecular weights both types approx. 23000. Neither enzyme contains any cyst(e)ine. However, most other respects they show little resemblance to the so far isolated. 3. Their properties, whether isolated cells (to which 50% is normally bound) or culture supernatant, appear be similar. weight a preparation strain 749/C obtained supernatant was found significantly (over 20%) higher than that alone. 4. With benzylpenicillin, 749 has Vmax. 6 times 6346, this difference `compensated' its being lower. Thus, at low biologically effective concentrations penicillin met with under natural conditions, where neither type more fraction saturated substrate, antibiotic hydrolysed same rate both. As expected, penicillin-sensitivities single were identical. 5. It suggested concept `physiological efficiency' (defined as divided Km), applied enzymes acting naturally conditions poor saturation their substrates, may useful for expressing biological function vivo.