NAD-Dependent Maltose Dehydrogenase and NAD-Dependent d-Glucose Dehydrogenase of Alkalophilic Corynebacterium sp. No. 150–1

An alkalophilic bacterium, strain No. 150–1, which had NAD-dependent sugar dehydrogenase activities on maltose (NAD-MalDH) and d-glucose (NAD-GlcDH), was isolated from soil. This microorganism was identificd to be in a strain of the genus Corynebacterium. The bacterium grew to similar degrees at Na₂CO₃ concentrations from 0 to 0.5%. NAD-MalDH and NAD-GlcDH were not inducible types. Soybean casein was the most effective nitrogen source for enzyme production. Activity staining of these two dehydrogense on polyacrylamide gel showed that these activities were derived from two different proteins. The cell free extract did not contain NADP-dependent maltose dehydrogenase.     

Interaction of Cytotoxic Bicyclic Peptides, Theonellamides A and F, with Glutamate Dehydrogenase and 17β-Hydroxysteroid Dehydrogenase IV

Theonellamide A, a bicyclic peptide isolated from a Theonella sponge, was fixed on hydrazide-containing gel beads and screened for its binding proteins from rabbit liver tissues. Analysis by sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed that two major proteins of 80 kDa and 55 kDa interacted with theonellamide A. The interaction between theonellamide A and two proteins was confirmed by competition experiments in which these two proteins failed to bind to theonellamide A–conjugated gel beads in the presence of theonellamide A or F. Amino-terminal amino acid sequence analysis of peptide fragments derived from the binding proteins by lysylendopeptidase digestion demonstrated that the 80-kDa and 55-kDa proteins were 17β-hydroxysteroid dehydrogenase IV and glutamate dehydrogenase, respectively. In an in vitro assay system, amination of α-ketoglutarate by glutamate dehydrogenase was activated with theonellamide F, although this effect was weaker than that with adenosine diphosphate, a well-known activator. Received October 15, 1999; accepted January 4, 2000.     

Purification and Characterization of α-Hydroxyglutarate Dehydrogenase from Alcaligenes sp.

NADH-dependent soluble l-α-hydroxyglutarate dehydrogenase (l-2-hydroxyglutarate: NAD⁺ 2-oxidoreductase) was found in a bacterium belonging to the genus Alcaligenes obtained from soil by citrate enrichment culture. A mutant with about 2.5-fold higher activity of the enzyme was derived from the bacterium and used as the enzyme source. High level of the enzyme was produced at the late stage of cultivation in the presence of citrate and with limited aeration. The enzyme was purified from the cells to homogeneity to give crystals, and its enzymatic properties were studied. The enzyme strongly reduced α-ketoglutarate to stereochemically pure l-α-hydroxyglutarate with NADH as a coenzyme, but it oxidized d-α-hydroxyglutarate with about 1/10 of the rate for l-form oxidation.     

L. plantarum,L. fermentum,and B. breve Beads Modified the Intestinal Microbiota and Alleviated the Inflammatory Response in High-Fat Diet–Fed Mice

Probiotics and Antimicrobial Proteins - This paper aims to study the effects of compound microbe-based beads on changes in the intestinal microbiota and alleviation of high-fat (HF)...     

Composition of Esterase and Peroxidase Isoenzyme Complex, Zein-2 Protein Fraction, and SDS-Protein Complex of Zea Mays L. × Tripsacum Dactyloides L. Hybrids and Parents

The patterns of esterase and peroxidase isoenzymes, subunits of zein-2 fraction and protomers of SDS-protein complex of Zea mays L. × Tripsacum dactyloides L. hybrids and their parents were compared. The study has been made to detect specific to Tripsacum isoesterases and isoperoxidases, zein subunits and SDS-protein protomers which could be used as markers for introgression of gene loci encoding these proteins from Tripsacum into hybrids of Tripsacum with Zea mays. Isoesterases and isoperoxidases as well protomers of SDS-protein complex specific to Tripsacum were detected in all hybrids analyzed. Zein subunits, specific to Tripsacum were detected in some of the analyzed hybrids which i that introgression frequency of the loci encoding proteins studied was different. Chromosome counts taken on the examined hybrids showed the addition of 9 – 13 Tripsacum chromosomes to maize chromosome complement.     

Purification and Properties of NADP-Dependent Maltose Dehydrogenase Produced by Alkalophilic Corynebacterium sp. No. 93–1

NADP-dependent maltose dehydrogenase (NADP-MalDH) was completely purified from the cell free extract of alkalophilic Corynebacterium sp. No. 93–1. The molecular weight of the enzyme was estimated as 45,000~48,000. The enzyme did not have a subunit structure. The isoelectric point of the enzyme was estimated as pH 4.48. The pH optimum of the enzyme activity was pH 10.2, and it was stable at pH 6 to 8. The temperature optimum was 40°C, and the enzyme was slightly protected from heat inactivation by 1 mm NADP. The enzyme oxidized d-xylose, maltose and maltotriose, and the Km values for these substrates were 150mm, 250 mm and 270 mm, respectively. Maltotetraose and maltopentaose were suitable substrates. The Km value for NADP was 1.5 mm with 100mm maltose as substrate. The primary product of this reaction from maltose was estimated as maltono-δ-lactone, and it was hydrolyzed non-enzymatically to maltobionic acid. The enzyme was inhibited completely by PCMB, Ag⁺ and Hg²⁺.