Kuniaki Hosono

Kinetic resolution of chiral metallocenic aldehydes and alcohols with liver alcohol dehydrogenase

Abstract Horse liver alcohol dehydrogenase-catalyzed oxidoreduction was useful to resolve racemic 1-formyl-2-methyl derivatives of tricarbonyl(cyclopentadienyl)manganese and (benzene)tricarbonylchromium and racemic 1-hydroxyethylferrocene, ruthenocene and osmocene.

Stereoselectivity of horse liver alcohol dehydrogenase catalyzed oxidoreduction of an organometallic meso diol and the corresponding dialdehyde

Abstract 1,2-Bis(hydroxymethyl)ferrocene was oxidized by horse liver alcohol dehydrogenase preferentially to (I R , 2 S )-(hydroxymethyl)aldehyde, while 1,2-diformylferrocene was reduced to the (1 S , 2 R )-antipode.

Stereoselective microbial reduction of planar chiral and prochiral organometallic aldehydes

SummaryCandida boidinii IAM 12269 andNocardia erythropolis IAM 12122 were useful for the asymmetric reduction of 1,2-diformylferrocene (1) to the planar chiral semialdehyde3 and for the optical resolution of (±)-tricarbonyl(2-methylbenzaldehyde)chromium (4) and (±)-tricarbonyl(1-formyl-2-methylcyclopentadienyl)manganese (6) having planar chirality.

Lipase-mediated homotopic and heterotopic double resolutions of a planar chiral organometallic alcohol

Summary(±)-Tricarbonyl η6-3-methylbenzyl alcohol)chromium was resolved to of ∼100%e.e. and of 92%e.e. by lipase-catalyzed transesterifications arranged in homotopic and heterotopic double resolutions.

High-performance liquid chromatographic determination of optical purity of planar chiral organometallic compounds resolved by enzymic transformations

Abstract The enantiomers of planar chiral organometallic compounds, i.e., 1-hydroxymethyl-2-methyl, 1-acetoxymethyl-2-methyl and 1-methoxycarbonyl-2-methyl derivatives of (η6-benzene)tricarbonylchromium, tricarbonyl(η5-cyclopentadienyl)manganese and ferrocene, and their 3-methyl analogues, were separated by high-performance liquid chromatography with a Chiralcel OD column. This method was useful to determine the optical purity for the above compounds formed in enzymic transformations.

ATP regeneration by cyclic photophosphorylation using spinach thylakoid

SummaryATP photophosphorylation by spinach thylakoid was examined to evaluate its use as an ATP regeneration reaction in biosynthetic reactors that consume ATP. Initial rate of cyclic photophosphorylation mediated by phenazine methosulfate was found to be 218 μmole ATP/h.mg Chlorophyll. This activity was stable for over 3 months at −85°C. When phosphoryl transfer reactions were coupled to cyclic photophosphorylation, ATP was continuously regenerated by thylakoid between 14–24 times in batch reactors.

Microbial asymmetric oxygenation of an organometallic sulfide

SummaryPenicillium frequentans IFO 5692 oxidized enantioselectively (methylthiomethyl)ferrocene (1) to (R)-(−)-(methylsulfinylmethyl)ferrocene (2) (≥98 %e.e.) andCorynebacterium equi IFO 3730 to (S)-(+)-2 (69 %e.e.).

Purification and some properties of a novel racemase, which racemizes 2-oxothiazolidine-4-carboxylic acid and 5-oxoproline, from Flectobacillus sp. strain B-1

A novel racemase active toward 2-oxothiazolidine-4-carboxylic acid was purified 310-fold with 5% recovery to near homogeneity from a crude extract of Flectobacillus sp. B-1, which had been isolated as a bacterium being able to assimilate (S)-2-oxothiazolidine-4-carboxylic acid. The molecular weight was estimated to be 92,000 by gel filtration. The purified preparation migrated as a single band of molecular weight 49,000 upon SDS-polyacrylamide gel electrophoresis. The enzyme exhibited maximum activity at pH 8.0 and 45 degrees C. The enzyme also racemized 5-oxoproline but did not act on proline and 4-hydroxyproline. The enzyme apparently had no coenzyme requirement. The enzyme activity was inhibited to 62-100% by SH-blocking reagents such as HgCl2, AgNO3, PCMB, iodoacetamide, N-ethylmaleimide and N-bromosuccinimide.

Asymmetrie Reduction of Synthetic Ketones by Marine Microorganisms

Abstract Three strains of bacteria reducing (trifluoroacetyl)ferrocene (3) to optically pure (R)-2,2,2-trifluoro-l-hydroxyethylferrocene (4) and one bacterial strain reducing 3 to (S)-4 of moderate optical purity were isolated from sea-water collected at the coastal areas in Ibaraki prefecture of Japan. The former three strains were identified as Micrococcus lylae, Micrococcus luteus, and Deleya marina and the latter as Bacillus licheniformis. These strains also asymmetrically reduced some other synthetic ketones, e.g., 2,2,2-trifluoroacetophenone (7) and phenyl trimethylsilyl ketone (9). Further screening of microorganisms capable of reducing 3 was done with bacteria isolated from sea-water of the deep sea (Okinawa trough, Japan trench, and Mariana trough) and of the pelagic areas (Indian Ocean and South China Sea). Most of these marine strains preferentially reduced 3 to (R)-4 similar to the coastal strains, but the frequency of finding very highly enantioselective strains (i.e., those forming 4 of > 90% e.e.) was remark ably high in several sites of the deep sea and pelagic areas as compared with the coast and terrestrial environment.

Continuous ATP production by spinach thylakoid in a stirred tank reactor

Abstract Spinach thylakoid was immobilized by two different methods for the purpose of retention within a continuous-flow stirred tank reactor (CSTR). The glutaraldehyde crosslinked albumin polymer method completely inactivated the cyclic ATP photophosphorylation of thylakoid. In contrast, agarose-entrapped thylakoid retained about 17% of the activity of the cyclic photophosphorylation of non-immobilized thylakoid. This activity declined continuously during ATP production in the CSTR. Fifty percent of the initial activity was lost within about 5.5 h. Ascorbate was found to increase the stability of ATP photophosphorylation; about twice as much ATP was produced at the optimal ascorbate concentration of 5 mM. Under the optimal dilution rate of 2.36 h −1 , about 60 μmol of ATP per mg chlorophyll were produced in 20 h by agarose-entrapped thylakoid in the CSTR. These results showed that, compared to non-immobilized thylakoid in batch operation, agarose-entrapped thylakoid produced only a low amount of ATP under continuous operation.