THE HYDANTOIN AMIDOHYDROLASE FROM ARTHROBACTER-AURESCENS DSM-3745 IS A ZINC METALLOENZYME

The hydantoin amidohydrolase (hydantoinase) from Arthrobacter aurescen s DSM 3745 was purified to homogeneity and subjected to metal analysis under atomic absorption spectrometry (AAS) and inductive coupled plas ma-atomic emission spectrometry (ICP-AES). Three independent preparati ons of homogeneous enzyme indicated that 1 mol of the active enzyme co ntains 10 mol zinc ions. This corresponds to 2.5 mol zinc per mol subu nit, since the hydantoinase consists of four identical subunits. Only trace amounts of manganese, magnesia, nickel and cobalt were detected. Other metals were either absent or existed below detection levels. (C ) 1998 Elsevier Science B.V. All rights reserved.