Sadafumi Omura

Transformation of vitamin D3 to 1α,25-dihydroxyvitamin D3 via 25-hydroxyvitamin D3 using Amycolata sp. strains

To enzymatically synthesize active metabolites of vitamin D3, we screened about 500 bacterial strains and 450 fungal strains, of which 12 strains were able to convert vitamin D3 to 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] via 25-hyroxyvitamin D3 [25(OH)D3]. The conversion activity was only detected in strains belonging to the genus Amycolata among all the organisms tested. A preparative-scale conversion of vitamin D3 to 25(OH)D3 and 1α,25(OH)2D3 in a 200-1 tank fermentor using A. autotrophica FERM BP-1573 was accomplished, yielding 8.3 mg 25(OH)D3/l culture and 0.17 mg 1α,25(OH)2D3/l culture. A related compound, vitamin D2, could be also converted to 25-hydroxyvitamin D2 and 1α,25-dihydroxyvitamin D2 using the same strain. The cytochrome P-450 of FERM BP-1573 was detected by reduced CO difference spectra in whole-cell suspensions. Vitamin D3 in the culture induced cytochrome P-450 and the conversion activity simultaneously, suggesting that the hydroxylation at C-25 of vitamin D3 and at C-1 of 25(OH)D3 originates from cytochrome P-450.

Application of cyclodextrin to microbial transformation of vitamin D3 to 25-hydroxyvitamin D3 and 1α,25-dihydroxyvitamin D3

Abstract Amycolata autotrophica converts vitamin D3(VD3) to 1α,25-dihydroxyvitamin D3(1α,25(OH)2VD3) via 25-hydroxyvitamin D3(25(OH)VD3) by hydroxylation of VD3 at C-25 and C-1. In this microbial hydroxylation, it was found that cyclodextrin (CD) had the ability to enhance the hydroxylation of VD3. Addition of partially-methylated-β-cyclodextrin (PMCD) increased the productivity of 25(OH)VD3 about seven-fold compared to that without CD. Combined use of PMCD and γ-CD increased the production of 1α,25(OH)2VD3 in a tank fermentor about sixteen-fold compared to that without CD.

Effect of E-64, Thiol Protease Inhibitor, on the Secondary Anti-SRBC Response In Vitro

E‐64, L‐trans‐epoxysuccinyl‐leucylamido (4‐guanidino) butane, a specific inhibitor of thiol proteases originally isolated from the culture of a fungus, was examined in connection with the immune responses to the splenocytes of mice.