[en] The DD-carboxypeptidase-endopeptidase of low penicillin sensitivity that is excreted by Streptomyces albus G has been crystallized from a polyethylene glycol (Mr 6000 to 7500) solution at pH 8.0. X-ray examination of the prismatic crystals shows that the space group is P21 with unit cell dimensions a = 51.1 Å, B = 49.7 Å, C = 38.7 Å, β = 100.6 ° and one molecule in the asymmetric unit. A crystal suspension made in 50 mM -Tris • HCl buffer (pH 8.0) supplemented with 5 mM-MgCl2 and 16% (w/v) polyethylene glycol exhibits enzyme activity on the substrate Ac2-L-Lys-D-Ala-D-Ala.
Ghuysen, Frère, Leyh-Bouille, Coyette, Dusart, Nguyen-Distèche (1979) Use of model enzymes in the determination of the mode of action of penicillins and delta 3-cephalosporins. Annu Rev Biochem, in the press; .
