| 摘要 |
1,261,711. Penicillin acylase. ASTRA A.B. 5 March, 1969 [15 Feb., 1968; 3 Dec., 1968], Nos. 7544/68 and 57373/68. Heading C3H. [Also in Division C2] A cell-free penicillin acylase composition is prepared by centrifuging cells of a penicillin acylase-producing strain of Escherichia coli at 0‹ to 50‹ C. in a self-cleaning centrifugal separator under conditions which apply to the cells a centrifugal pressure of 500 to 2000 p.s.i. and intermittently expelling the cells through an orifice to effect sudden decompression on the cells and thereby release the intracellular penicillin acylase therefrom, then extracting the released acylase into an aqueous medium at 10‹ to 50‹ C. for 0À1 to 0À5 hour and separating the aqueous extract from the cell debris. The E. coli is preferably cultivated in a medium containing phenyl-acetic acid and corn-steep liquor, the culture being saturated with butyl, isobutyl or amyl acetate before the centrifugation treatment, to kill the cells. The expulsion orifice is preferably a slit of width 0À1 to 1À5 mm. The preferred extracting medium is water containing 1-5% by volume of water-immiscible solvent, e.g. methyl isobutyl ketone, butyl, isobutyl or amyl acetate, benzene, toluene or chloroform, and an inorganic or organic base to bring the pH to 6À5 to 9À0. The cell debris is filtered or centrifuged off, after which the extract may be purified by precipitating impurities with acids or alkalies, treatment with ionexchangers, precipitation as a tannin complex which may either be dried or redissolved (e.g. in organic solvent or water at pH 7-9) and the solution freed from tannin with an ionexchanger, dialysis, ultra-filtration, deproteinization with carboxymethyl cellulose, or gelfiltration. The solution may finally be dried (e.g. by lyophilization or float-drying) or else the enzyme may be precipitated with ammonium sulphate or adsorbed on to an activated (cyanogen-treated) polysaccharide. The acylase compositions are for use in preparing 6-aminopenicillanic acids (see Division C2). Reference has been directed by the Comptroller to Specifications 897,617 and 893,418.
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