ZNG1B is a zinc chaperone that functions as a GTP-dependent zinc transferase, directly transferring zinc cofactors to activate target metalloproteins 1. Structurally, ZNG1B contains an N-terminal psi-PxLVp motif and a CXCC motif within its GTPase domain that mediates zinc binding and transfer. Its primary substrate is methionine aminopeptidase 1 (METAP1), an essential protein that cleaves initiator methionines during protein maturation. ZNG1B catalyzes zinc insertion into METAP1's active site through a mechanism requiring GTP hydrolysis and subsequent GTP/GDP exchange for release of the activated enzyme 1. Deletion of ZNG1 in yeast results in defective METAP1 function and zinc-deficiency growth defects, demonstrating the physiological importance of zinc transfer 1. ZNG1B operates in both cytoplasmic and nuclear compartments, positioning it to support zinc-dependent protein maturation across cellular environments. While the provided abstracts do not directly establish ZNG1B mutations in human disease, the functional dependence on ZNG1 for METAP1 activation and the broader relevance of zinc chaperones in human development suggest potential relevance to metal homeostasis-dependent pathologies, though specific clinical significance remains to be determined.