It was confirmed that Δ5, 7-sterol Δ7-reductase activity was suppressed by cholecalciferol (vitamin D3) in the enzyme system consisted of microsomes and sterol carrier protein (SCP). The enzyme activity was significantly decreased in the combination with microsomes obtained from either vitamin D-deficient or vitamin D3-treated rat liver and with SCP obtained from vitamin D3-treated rat. It was also demonstrated by the binding assay of the dextran-charcoal technique that 7-dehydrocholesterol binding to SCP could be specifically displaced by vitamin D3. The inhibition of cholecalciferol on 7-dehydro-cholesterol binding to liver SCP was confirmed to be non-competitive inhibition.
Although cataract was recognized as a typical symptom of ariboflavinosis soon after the discovery of riboflavin, some reports appeared thereafter which denied its occurrence. In the present study electron microscopic examination of the lens of rat fed on synthetic riboflavin-deficient diet revealed swelling degeneration of mitochondria and vacuolation of cytoplasm of the epithelial cells of the lens. These changes are similar to those observed in the initial period of cataract caused by other agents.
1. Studies carried out in cell-free rat-liver extracts showed an inhibitory effect of thiamine deficiency on porphyrin synthesis. 2. Extracts of normal and thiamine-deficient rat livers were incubated with the cofactors and substrates of the thiamine pyrophosphate-dependent enzyme, 2-oxoglutarate glyoxylate carboligase. There was a marked inhibition of porphyrin synthesis when the substances were added either individually or together. 3. Thiamine deficiency resulted in a decrease of haemoglobin concentration and catalase activity whereas a rise in tryptophanpyrrolase activity and cytochrome b5 and P450 concentration was observed.
1. The natural abundance carbon-13 nmr of vitamins D (D2 and D3) and several isomers (5, 6-trans-vitamin D2, isotachysterol2 and isovitamin D2) have been completely assigned by employing offresonance noise-decoupling, acetylation shifts, and lanthanide-induced shifts experiments. The last two techniques were especially useful for the present study. 2. Carbon-13 nmr spectral characteristics of the three main conjugated triene moieties (sE-Z-sZ, sE-E-sZ, or sE-E-sE), involved in the molecules of vitamin D and its isomers, were revealed. Thus, the striking dependence of the shieldings on molecular geometries and high sensitivity of the resonances to the environments of conjugated systems were surveyed. 3. Conformational preferences in solutions of the hydroxyl groups in vitamins D2 and D3 as well as 5, 6-trans-vitamin D2 were conveniently determined.
A trypsin inhibitor was extracted from eggplant exocarps with several buffers. The 0.1M acetate buffer, pH 5.5, extract had the highest specific activity. The crude inhibitor, obtained by heat treatment and salting-out from the acetate buffer extract, contained 4.5 nitrogen and 22.6% hexose. Isoelectrofocusing demonstrated that this crude inhibitor in the eggplant exocarps was composed of at least three forms, one of which differed in its isoelectric point. The form at pH 4.7 had the strongest activity. The molecular weights of these inhibitors were estimated to be between 5.000-10.000 by gel filtration.
A proteinase inhibitor was isolated and partially purified from the exocarp of eggplant, Solanum melongena L., by means of acetate buffer extraction, heat treatment, salting-out and column chromatography on DEAF-cellulose. This preparation showed inhibitory activities on various proteinases; trypsin [EC 3. 4. 4, 4] and Pronase were strongly inhibited while α-chymotrypsin [EC 3. 4. 4. 5] and Nagarse were weakly inhibited. The inhibitor was a protein substance, and, therefore, it was gradually inactivated by the long-time incubation with Pronase. The inhibition mode was non-competitive on trypsin and competitive on Pronase on the basis of Lineweaver-Burk plots. The investigations on the inhibition behavior in the co-existence of two kinds of proteinases suggested that the inhibitor was not of multi-headed type.
The experiments were designed to study the effects of exercise of various intensities in albino rats fed diets containing 8per cent or 20per cent casein. Male rats about 7 weeks old were divided into exercise groups and control (non-exercise) groups. The exercise groups were forced to run 57km or 76km in total during a 28-day period. The oxygen uptake of rats was measured in order to study the influence of exercise on energy metabolism of rats and the effects of training. Body weight and food intake were also measured. 1. In all exercise groups the total amount of food intake and body weight gain during the exercise period were smaller than those of the control groups, regardless of the protein levels of the diets. But while the rats were kept at rest after the exercise period, the food intake and body weight of these groups increased and approached those of the control groups. 2. No difference in resting metabolism was observed both in the 8per cent and 20per cent casein groups. At lower speeds up to 1.5km/hr the 8 per cent casein group indicated lower oxygen requirement during the exercise but at speeds higher than 2.0km/hr the oxygen requirement was definitely higher than that of the 20per cent casein group. The estimated optimum speed for rats weighing 300g on the average is some-where between 1.5 and 2.0km/hr if calculated on the basis of oxygen requirement for running 100m. 3. The obvious effects of training on oxygen uptake were seen in the 20per cent casein group after four weeks' training, although no effect was found in the 8 per cent casein group.