Cephalosporinase reaction

Response Curve of the Electrode. From Nernst s formula, the membrane potential of the glass electrode is proportional to the logarithm of the proton concentration. Protons are liberated from the cephalosporinase reaction. Therefore, hydrogen ion concentration in a sample solution measured by the pH electrode is proportional to the logarithm of the cephalosporin concentration... 

Cephalosporine Sensor. Simple, continuous methods for antibiotic determination are required for fermentation industries. Citrobacter freundii produced cephalosporinase, which catalyzes the following reaction of cephalosporin, which liberates hydrogen ions ... 

The accumulation of results presented so far suggested that the biosynthesis of the cephalosporins and penicillins was essentially the same in many respects and that, like the penicillins, the cephalosporins were probably derived from a-aminoadipylcysteinylvaline. The cephalosporin producing organisms that have been most studied to date (C. acremonium and S. clavuligerus) both also produce penicillin N. There are, therefore, two possible routes from the tripeptide to the cephem products, one by direct cyclisation of the tripeptide, the other by enzymic ring expansion of penicillin N. The first evidence that penicillin N could be converted enzymically to a cephalosporin was provided by Kohsaka and Demain 289) who demonstrated that lysed protoplasts of C. acremonium could convert penicillin N to another antibiotic or antibiotics which were destroyed by cephalosporinase but not by penicillinase. The product of this cell-free enzymic reaction was characterised as deacetoxycephalosporin C (297) by Yoshida etal. 290). These authors also showed that cell-free... 

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