Isopenicillin N synthase (IPNS) is a nonhaem-Fe²⁺-dependent enzyme that belongs to a class of nonhaem Fe²⁺-containing enzymes, which includes 2-oxoglutarate-dependent dioxygenases, 2-oxoglutarate-dependent hydroxy-lases, and enzymes involved in ethylene formation and anthocyaninidinbiosynthesis. IPNS catalyses the stereospecific formation of the beta-lactam and thiazolidine rings of IPN via a 4-electron oxidation of the tripeptideACV. The enzyme uses, as the sole electron acceptor, one molecule ofdioxygen, which is completely reduced to two molecules of water. The oxygen stoichiometry shown by IPNS is the same as that for cytochrome C oxidase,but is unusual for nonhaem-iron-containing enzymes, which typically catalysethe transfer of one or both atoms of dioxygen into their substrates. IPNSthus provides an interesting contrast to dioxygenase enzymes.

All IPNS proteins reported to date have a molecular mass of 30-40kDa andare highly conserved. The degree of identity in the predicted amino acidsequence ranges from 54-75%. Two cysteines are invariant in all known IPNSsequences; these residues are believed to be functionally important foriron binding. Histidine and aspartic acid residues in the sequenceconstitute the endogenous ligands of the ferrous active site.

Isopenicillin N synthase (IPNS) is a nonhaem-Fe²⁺-dependent enzyme that belongs to a c
Show more...

Download genes (select columns to include)