A strain of Pseudomonas putida was isolated by selective enrichment with morphine that was capable of utilising morphine as a primary source of carbon and energy for growth. Experiments with whole cells showed that both morphine and codeine, but not thebaine, could be utilised. A novel NADP-dependent dehydrogenase, morphine dehydrogenase, was purified from crude cell extracts and was shown to be capable of oxidising morphine and codeine to morphinone and codeinone, respectively. This NADP-dependent morphine dehydrogenase was not observed in any other species of pseudomonads examined and was quite distinct from the beta-hydroxysteroid dehydrogenase found in Pseudomonas testosteroni, which had previously been shown to have activity against morphine.

The NADP(+)-dependent morphine dehydrogenase that catalyses the oxidation of morphine to morphinone was detected in glucose-grown cells of Pseudomonas putida M10. A rapid and reliable purification procedure involving two consecutive affinity chromatography steps on immobilized dyes was developed for purifying the enzyme 1216-fold to electrophoretic homogeneity from P. putida M10. Morphine dehydrogenase was found to be a monomer of Mr 32,000 and highly specific with regard to substrates, oxidizing only the C-6 hydroxy group of morphine and codeine. The pH optimum of morphine dehydrogenase was 9.5, and at pH 6.5 in the presence of NADPH the enzyme catalyses the reduction of codeinone to codeine. The Km values for morphine and codeine were 0.46 mM and 0.044 mM respectively. The enzyme was inhibited by thiol-blocking reagents and the metal-complexing reagents 1,10-phenanthroline and 2,2'-dipyridyl, suggesting that a metal centre may be necessary for activity of the enzyme.

A heat-stable factor, required for de novo synthesis of fatty acids in the erythromycin-producing organism Streptomyces erythraeus, has been purified to homogeneity and identified as an acyl carrier protein (ACP). We conclude that, contrary to previous belief, fatty acid synthase in S. erythraeus more closely resembles the dissociable complex of E. coli than the tightly associated, multifunctional enzyme complex found in the related actinomycete Mycobacterium smegmatis.Fatty acid synthase; Acyl carrier protein; (Streptomycetes)

A strain of a Rhodococcus sp. (termed H1) capable of utilizing heroin as its sole carbon and energy source was isolated by selective enrichment. An inducible heroin esterase was partially purified and shown to catalyze the hydrolysis of both of the acetylester groups of heroin. The enzyme displays optimum activity at pH 8.5 and appears to be a trimer of identical subunits with an Mr of 39,000 and a native Mr of 120,000.

The structural gene, adhA, for a thermostable primary alcohol dehydrogenase was cloned from Thermoanaerobacter ethanolicus JW200. Constitutive expression from its own promoter was observed in Escherichia coli. The nucleotide sequence of adhA corresponded to an open reading frame of 1197 bp, encoding a polypeptide of 399 amino acids with a calculated Mr of 43 192. Amino acid sequence analysis showed 67-69% identity with alcohol dehydrogenases from two archaeal species and 29-37% identity with bacterial type III alcohol dehydrogenases. This represents the first reported cloning of an alcohol dehydrogenase from a bacterial species that is both thermostable and active against primary long-chain alcohols.