The cephalosporin acylases are a group of enzymes that hydrolyze cephalosporin C and/or glutaryl 7-aminocephalosporanic acid to produce 7-aminocephalosporanic acid.The cephalosporin acylase from Pseudomonas sp.strain 130 was crystallized in two different forms suitable for structural studies.A tetragonal crystal form diffracted to 0.24 nm belonged to the space group P41212.There was one αβ heterodimer per asymmetric unit.A second crystal form diffracted to 0.21 nm belonged to the space group P21.There was four αβ heterodimers per asymmetric unit.The tetragonal crystal structure of CA-130 was determined using the multiwavelength anomalous diffraction method and the P21 crystal structure was then determined using the molecular replacement method.