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an s Broc km ann nnd G iin t er Schmidt -Has t ner : Valinomycin I, XXVII. Mitteil. iiber Antibiotics am Actinomycetenl)

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Optically active D-arylglycines, which are of interest for preparation of semisynthetic penicillins and cephalosporins, were isolated from the racemic mixtures of their derivatives using immobilized proteolytic enzyme subtilisin (EC No. 3.4.4. 16). The performance of these reactions in two-phase systems, consisting of water and an immiscible organic solvent, improved the yield, purity, and economics of the process by increasing the substrate solubility and reducing the rate of nonenzymatic hydrolysis. The proportion of the organic phase can be as much as 75% of the overall volume without seriously impairing the enzymatic activity. The optically pure D-and L-arylglycines were liberated from their D- and L-derivatives by acid hydrolysis. The substituent influence of the various arylglycine derivatives on the rate of the enzymatic cleavage reaction was investigated.

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