Lactamase Beta (LACTb)

LACTB encodes a protein from the large 39S subunit of the mitochondrial ribosome. LACTb has some sequence similarity to prokaryotic beta-lactamases but most of the residues that are responsible for the beta-lactamase activity are not conserved between the two proteins.The deduced 551-amino acid Lactb protein contains an N-terminal transmembrane domain and an alpha/beta-hydrolase fold catalytic site. LACTB, which encodes a predicted 549-amino acid protein that shares 90% amino acid identity with mouse Lactb. Northern blot analysis of mouse tissues detected expression at high levels in liver, heart, and skeletal muscle, with lower levels in kidney, testis, brain, lung, and spleen. Northern blot analysis of human tissues detected a 2.3-kb transcript expressed at high levels in heart and skeletal muscle.