The ammonia monooxygenase (AMO) of Nitrosomonas europaea is a metalloenzyme that catalyses the oxidation of ammonia to hydroxylamine. We have identified histidine 191 of AmoA as the binding site for the oxidized mechanism-based inactivator acetylene. Binding of acetylene changed the molecular mass of His-191 from 155.15 to 197.2 Da (+42.05), providing evidence that acetylene was oxidized to ket...

We propose that the ubiquitous process of Cd homeostasis is likely to outweigh any physiological use of Cd (in place of Zn) in driving oceanic Cd cycling. This is based on the observation that, in our experiments, the Cd-isotopic composition of cultured microbes was independent of the presence/absence of the CdCA1 metalloenzyme (Cd carbonic anhydrase; the only known biochemical function for Cd)...

The protease from Chromohalobacter japonicus BK-AB18 was produced by growing bacteria in a LB medium containing 5% casein and NaCl. crude partially purified three levels of ammonium sulfate concentration (ranges 0–70%, 70–75% 75–80%) the highest specific activity exhibited range 75–80%. enzyme has relative molecular weight 65 kDa. this fraction had following optimum conditions: 7.5% NaCl, pH 9....

The inhibition of yeast alcohol dehydrogenasel activity produced by 1, lo-phenanthroline, a zinc-binding reagent, has been studied intensively as an example of the action of a chelating agent on a metalloenzyme. The data (l-3) indicate that OP brings about two distinct types of inactivation of YADH: (a) an instantaneous2 and reversible inhibition and (b) a time-dependent and irreversible inhibi...

The zinc-metalloenzyme GlcNAc-PI de-N-acetylase is essential for the biosynthesis of mature GPI anchors and has been genetically validated in the bloodstream form of Trypanosoma brucei, which causes African sleeping sickness. We screened a focused library of zinc-binding fragments and identified salicylic hydroxamic acid as a GlcNAc-PI de-N-acetylase inhibitor with high ligand efficiency. This ...

The preparation of hybrid transition metalloproteins by thiol-selective incorporation of organometallic rhodium- and ruthenium complexes is described. Phosphine ligands and two rhodium-diphosphine complexes bearing a carboxylic acid group were coupled to the cysteine of PYP R52G, yielding a metalloenzyme active in the rhodium catalyzed hydrogenation of dimethyl itaconate. The successful couplin...