May be required for DNA interstrand cross-link repair. Also required for checkpoint mediated cell cycle arrest in early prophase in response to mitotic spindle poisons. Possesses beta-lactamase activity, catalyzing the hydrolysis of penicillin G and nitrocefin (PubMed:31434986). Exhibits no activity towards other beta-lactam antibiotic classes including cephalosporins (cefotaxime) and carbapenems (imipenem) (PubMed:31434986). a beta-lactam + H2O = a substituted beta-amino acid Beta-lactamase activity is inhibited by sulbactam. Binds constitutively to TP53BP1. Binds CDC27, which is itself a component of the anaphase promoting complex (APC). Binds PIAS1. In some cells it may be found in typically 1 or 2 discrete nuclear aggregates of unknown function which also contain TP53BP1. Also found in multiple discrete nuclear foci which increase in number following treatment with ionizing radiation or interstrand cross-linking agents. These foci overlap with those formed by the MRN complex (composed of MRE11, RAD50 and NBN) and BRCA1. Expressed in brain, heart, kidney, liver, pancreas, placenta and skeletal muscle. During mitosis. The mRNA encoding this protein contains an internal ribosome entry site (IRES) in its 5'-UTR. This 5'-UTR generally suppresses translation while specifically promoting expression during mitosis, when cap-dependent translation may be impaired. Belongs to the DNA repair metallo-beta-lactamase (DRMBL) family. Extended N-terminus.