Glutamate decarboxylase (GAD) [EC 4.1.1.15] was purified from a cell-free extract of Lactobacillus brevis IFO 12005 by chromatographies on Sephadex G-100, DEAE-Sepharose CL-6B, and Mono Q. About 9 mg of purified GAD was obtained from 90.2 g of wet cells. The purified preparation showed a single protein band on SDS-PAGE. The molecular weights of purified GAD by SDS-PAGE and gel filtration on Superdex 200 were 60,000 and 120,000, respectively, indicating that GAD from L. brevis exists as a dimer. The N-terminal amino acid sequence of the purified GAD was NH2-Met-Asn-Lys-Asn-Asp-Gln-Glu-Gln-Thr-. The optimum pH and temperature of GAD were at pH 4.2 and at 30 degrees C. The GAD activity was increased by the addition of sulfate ions in a dose-dependent manner. The order of effects was as follows: ammonium sulfate > sodium sulfate > magnesium sulfate, indicating that the increase of hydrophobic interaction between subunits causes the increase of GAD activity. The purified GAD reacted only with L-glutamic acid as a substrate and the K(m), kcat, and kcat/K(m) values were 9.3 mM, 6.5 S-1, and 7 x 10(2) M-1 S-1, respectively.

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Photochemical isomerization of trans-azobenzene to ds-isomer, and its inverse cis-trans isomerization were investigated for the purpose of constructing a thermal energy storage system by conversion of solar light energy.Trans-cis photoisomerization of azobenzene in the cyclohexane solution proceeded with or without photosensitizers over a wide range of light in the ultraviolet and visible region. But the backward reaction from cis-to trans-form, which was predominant by the longer-wavelength light, set a limit to the progress of trans-cis conversion, and photochemical equilibrium was established at about 25 % conversion of mmv-azobenzene. Some devices to removethe conversion limit were examined. Cis-trans isomerization in the dark was carried out in the presence of immobilized metal porphine catalyst. Cotetraphenylporphine or Co-protoporphyrin fixed on polyethylene granules graft-polymerized with chloromethylstyrene was the most effective for the reverse reaction. This liberation of heat during the reaction was also analyzed from the kinetic point of view.

Lactobacillus brevis IFO-12005 showed good growth in rice shochu distillery lees (kome shochu kasu). Almost all of the free glutamic acid (10.50 mM) in shochu kasu was converted to gamma-amino-butyric acid (GABA) within 2 d of stationary culture at 30 degrees C. The amount of GABA in the kome shochu kasu medium finally reached 10.18 mM. After centrifugation of the broth culture, the supernatant fraction was treated with a flocculation agent to form a clear solution, then passed through a column containing a synthetic adsorbents, SP-207 to remove the yellow pigment and flavors which are unnecessary from a sensory perspective. An economical and simple production process for GABA was established.

Photosensitized isomerization of norbornadiene to quadricyclene was investigated by using several photosensitizers such as toluene, acetone, acetophenone, benzophenone and a-naphthoquinone. The effect of wavelength on the quantum yield of quadricyclene and on the energy conversion efficiency was measured by using spectroirradiator. The formation of byproduct polymer in the presence of photosensitizers was also studied. The formation of polymers during irradiation, which prevents the repeated use of energy storage material, was effectively suppressed by the addition of several phenolic substances into norbornadiene.