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Biomedical subjects

S Fukui

Publications and source records attributed to S Fukui.

At least 307 records · Page 17Linked to original sources
PubMed1977

A method for the estimation of peak serum LDH activity based on a single post-peak level after acute myocardial infarction.

A new method was developed to estimate the peak serum lactic dehydrogenase (LDH) value in patients with acute myocardial infarction from a single determination of serum LDH activity in the post-peak period (3rd to 5th day after the onset of infarction) using nomogram method based on the monoexponential decay of serum LDH with a decay constant of 0.012 hours-1. To develop this nomogram, the serial changes in serum LDH activities were studied in 30 patients with acute myocardial infarction admitted to the coronary care unit within the pre-peak period. The mean errors in estimation from data of the 3rd, 4th, or 5th day after the onset were acceptably small, 10.5 +/- 1.9%, 14.5 +/- 2.8%, and 15.9 +/- 3.3%, respectively. Furthermore, a correction formula was obtained to improve the accuracy of estimation, since the peak values were underestimated in patients with actual peak values less than 300 units and overestimated in the case of more than 500 units. Estimation in 9 patients of an external sample group confirmed that this nomogram is useful clinically with mean errors of less than 25%.

Acute Disease↗
PubMed1976

Isolation and characterization of hydrophobic proteins (H proteins) in the membrane fraction of Bacillus subtilis. Involvement in membrane biosynthesis and the formation of biochemically active membrane vesicles by combining H proteins with lipid.

Cytoplasmic membranes of Bacillus subtilis, grown in complex medium containing glucose, were fractionated into three membrane subfractions [light band (1.155 - 1.158 g/cm3); medium band (1.181 - 1.183 g/cm3); heavy band (1.21 - 1.25 g/cm3)] by sucrose density gradient centrifugation. Among these subfractions, the light and medium bands consisted mainly of membranes but the heavy band consisted of an irregular arrangement or aggregate of small globular protein components of 5 - 8 nm in diameter. We named this H-protein. H-protein formed trilamellar unit membrane structure when combined with lipid. In pulse-labeling and pulse-chase experiments with radioactive leucine, it was found that H-protein consisted of the newest membrane protein synthesized in the cells and the label incorporated into H-protein was shifted into light and medium band of the membranes during the chase. Cytochromes were not found in H-protein. However, when H-protein was incubated with haem alpha and protohaem, these compounds were incorporated into the apoproteins of the cytochromes present in H-protein and form cytochromes a and b. Cytochromes were also formed in H-protein which were isolated from the cells grown in the presence of haemin (haemin-grown H protein). Succinate dehydrogenase activity was increased about 4-fold by combining H-protein or haemin-grown H protein with lipid. H-protein had no cytochrome oxidase activity; however, haemin-grown H protein was found to have some of the activity and this was increased about 4-fold by combining the protein with lipid. Haemin-grown H protein was also found to form succinate: cytochrome c oxidoreductase when combined with lipid and vitamin K2. On the other hand, succinate oxidase was required for the addition of lipid, vitamin K2 and cytochrome c. NADH oxidase was also found in haemin-grown H protein and was activated about 9-fold in constituted reaction systems. Vesicles formed by haemin-grown H protein and lipid, could accumulate alanine and proline by addition of NADH or reduced phenazine methosulfate. Alanine and proline was also accumulated into the vesicles when transport energy was supplied as a membrane potential introduced by K+-diffusion via valinomycin. These results would indicate that H-protein contains the apoprotein of cytochromes, and a carrier involved in the active transport of alanine and proline.

Alanine↗
PubMed1976

Mechanism of inhibition of Chromatium D growth by L-methionine. Regulation of L-threonine biosynthesis by the intracellular level of S-adenosylmethionine.

(1) An unusual accumulation of S-adenosyl-L-methionine in Chromatium D was associated with a marked growth inhibition by L-methionine. The inhibition was overcome by L-isoleucine, L-leucine, L-phyenylalanine, L-threonine, L-valine and putrescien. Based on their effects, these compounds are classified into 3 types. (2) L-Isoleucine, L-leucine, L-phyenylalanine and L-valine (Type I) inhibited the L-methionine uptake and consequently prevented the bacterium from the unusual accumulation of S-adenosyl-L-methionine even in the presence of L-methionine in the medium. Putrescine (Type II) stimulated the consumption of S-adenosyl-L-methionine, but did not influence the L-methionine uptake. Hence, the effect of putrescine would be explained by the action to diminish the intracellular level of S-adenosyl-L-methionine. L-Threonine (Type III) neither inhibited the L-methionine uptake nor affected the content of S-adenoxyl-L-methionine due to the addition of L-methionine. (3) The specific activity of homoserine kinase (EC 2.7.1.39) was greatly lowered by the addition of L-methionine under conditions in which Chromatium D unusually accumulates S-adenoxyl-L-methionine. Homoserine dehydrogenase (EC 1.1.1.3) activity was inhbitied by S-adenosyl-L-methionine (50% inhibition index, 3.5 mM). These facts strongly suggest that the growth inhibition by L-methionine is associated with the L-threonine deficiency caused by the unusual accumulation of S-adenosyl-L-methionine.

Amino Acids↗
PubMed1976

Affinity chromatography of amine oxidase from Aspergillus niger.

Omega-Aminohexyl-Sepharose 4B served as an excellent biospecific adsorbent for affinity chromatography of amine oxidase (monoamine:O2 oxidoreductase (deaminating), EC 1.4.3.4) from Aspergillus niger. The enzyme was completely adsorbed on this affinity resin when applied to a column in 0.1 M potassium phosphate buffer (pH 7.2). Although a small part of the enzyme was retained on the column through ionic interaction and eluted with 1.0 M potassium phosphate buffer (pH 7.2), most of the enzyme adsorbed was eluted with 0.5 M potassium phosphate buffer (pH 7.2) containing 10 mM butylamine. Essentially no retention of the enzyme on a column of epsilon-aminopentyl-Sepharose or delta-aminobutyl-Sepharose occurred under the same conditions, indicating that an appropriate length (more than approx. 12 A) of a hydrocarbon extension between the agarose matrix and the terminal amino group would be necessary for efficient adsorption of amine oxidase. The modification of the enzyme with 3-methyl-2-benzothiazolinone hydrazone (carbonyl inhibitor) or dithionite (reducing agent) resulted in loss of the ability to bind to omega-aminohexyl-Sepharose. It was also demonstrated that the affinity chromatography on omega-aminohexyl-Sepharose can be used as a powerful means of purifying this enzyme from crude extracts of Aspergillus niger. All of the three adsorbents were effective as a substrate in the amine oxidase reaction, but their substrate activities were as low as the corresponding free diamines.

Aspergillus niger↗
PubMed1976

Studies on metabolic role of 5'-Methylthioadenosine in Ochromonas malhamensis and other microorganisms.

Several compound containing a thiomethyl group were found to replace vitamin B12 in a protozoan, Ochromonas malhamensis. The order of the effectiveness was as follows: 5'-methylthioadenosine is greater than S-adenosylmethionine is greater than 5-methylthioribose is greater then L-methionine. A similar order was obtained with respect to the permeability of these compounds into the protozoan cells, except for S-adenosylmethionine. 5'-Methylthioadenosine and 5-methylthioribose as well as L-methionine markedly increased the intracellular content of L-methionine. The level of S-adenosylmethionine was also increased by them, but to lesser degree. The thiomethyl group of the compounds was established to be incorporated into S-adenosylmethionine. The metabolic fate of the thiomethyl group of 5'-methylthioadenosine cannot be distinguished from that of L-methionine. A high activity of 5'-methylthioadenosine nucleosidase was detected in the cell-free extracts of the protozoan. These results strongly suggest that 5'-methylthioadenosine would be metabolized to L-methionine would be ocnverted to S-adenosylmethionine. Like L-methionine and vitamin B12, 5'-methylthioadenosine and 5-methylthioribose may play an important role in maintenance of the C-1 pool in Ochromonas malhamensis. Neither 5'-methylthioadenosine nor 5-methylthioribose replaced vitamin B12 in some vitamin B12-requiring bacteria. This result is consistent with the fact that neither compounds was significantly taken up by these bacteria.

Adenosine↗
PubMed1976

Acetyl-coenzyme-A carboxylase of Candida Lipolytica. 1. Purification and properties of the enzyme.

Acetyl-coenzyme-A carboxylase has been isolated in homogeneous form from Candida lipolytica. The homogeneity of the enzyme preparation is evidenced by analytical ultracentrifugation, dodecyl-sulfate-polyacrylamide gel electrophoresis and Ouchterlony double-diffusion analysis. The purified enzyme exhibits a specific activity of 8.0 U/mg protein at 25 degrees C and contains 1 mol biotin/263000 g protein. The sedimentation coefficient (S20,W) of the enzyme is 18 S. It has been shown by dodecyl-sulfate-polyacrylamide gel electrophoresis that the enzyme possesses only one kind of subunit with a molecular weight of 230000. This finding, together with the biotin content, indicates that the C. lipolytica enzyme has a highly integrated subunit structure. The C. lipolytica enzyme is very labile, but is stabilized by glycerol. The enzyme is markedly activated by poly(ethyleneglycol), the activation being due principally to a decrease in the Km values for substrates. Even in the presence of this activator, the Km value for acetyl-CoA of the C. lipolytica enzyme is much higher than that of the enzyme from Saccharomyces cerevisiae and animal tissues. The C. lipolytica enzyme, unlike the enzyme from animal tissues, is not activated by citrate.

Acetyl-CoA Carboxylase↗
PubMed1976

Acetyl-coenzyme-A carboxylase of Candida lipolytica. 2. Regulation of cellular content and synthesis of the enzyme.

The level of acetyl-coenzyme-A carboxylase activity in Candida lipolytica undergoes large variations depending upon the carbon source on which the yeast is grown. Cells grown on n-alkanes or fatty acids exhibit a lower activity level than do cells grown on glucose. Among the n-alkanes and fatty acids tested, n-heptadecane, n-octadecane, oleic acid and linoleic acid reduce the enzyme activity to the lowest levels, which are 16-18% of the activity level in glucose-grown cells. Immunochemical titrations and Ouchterlony double-diffusion analysis with specific antibody as well as kinetic studies have indicated that the observed decrease in the level of acetyl-CoA carboxylase activity is due to a reduction in the cellular content of the enzyme. Furthermore, isotopic leucine incorporation studies with the use of the immunoprecipitation technique have demonstrated that the relative rate of synthesis of the enzyme in oleic-acid-grown cells is diminished to 12% of that in glucose-grown cells. Evidence has also been obtained to support the view that the enzyme in this yeast is not degraded at a rate high enough to contribute to the marked decrease in the cellular content of the enzyme. Thus, it is concluded that the reduction in acetyl-CoA carboxylase content in fatty-acid-grown cells is due to diminished synthesis of the enzyme.

Acetyl-CoA Carboxylase↗
PubMed1976

Development of Microbodies in the yeast Kloeckera growing on methanol.

A number of microbodies appear regularly in methanol-grown yeast cells, but rarely in ethanol- or glucose-grown cells. When one of representative methanol-utilizing yeasts, Kloeckera sp.no. 2201 (also known as Candida bodinii), was cultured on glucose and then transferred into a methanol medium, microbodies of small size could be observed in 2-h old cells. The number of microbodies per sectioned cell reached five to six after 4 h of cultivation. Though the number of microbodies did not change during prolonged cultivation, their size became larger with the passage of cultivation time. The activities of catalase and alcohol oxidase were confirmed in the particulate fractions throughout the cultivation period, whereas the activities of formaldehyde dehydrogenase and formate dehydrogenase were not detected in the particles. The activity of isocitrate lyase was detected in the particulate fractions only at the early growth phase.

Alcohol Oxidoreductases↗
PubMed1976

Significance of serum enzyme changes after cardiac catheterization and selective coronary arteriography.

The serum creatine kinase (CK), aspartate transaminase (AST), lactic dehydrogenase (LD) and alpha-hydroxybutyric dehydrogenase (HBD) were determined before and 3, 6, 18, and 36 hours after cardiac catheterization and angiocardiography in 56 consecutive patients with ischaemic heart disease. Five of these patients whose serum enzyme levels were higher than normal before the procedure were excluded from the study. Forty-one of the remaining 51 patients had left ventriculography and also selective coronary arteriography. In these 41 patients (groups 1 and 2--see below), the mean serum CK levels increased after the procedure to exceed the upper limit of normal at every study interval. The mean serum AST, LD, and HBD levels generally remained within the normal range at all study intervals, though serum AST increased abnormally in 9 of the 41 patients (22%) and serum LD and HBD each increased above the normal limit in 2 of 41 patients (4.9%). In 24 patients (group 1) whose coronary arteriograms showed insignificant coronary narrowing (less than 75%) in any of the three major coronary arteries, the increase in serum CK was significantly higher than in 17 patients (group 2) with greater than 75% narrowings in at least one of the three major coronary arteries. However, the degree of serum CK elevation observed during the postangiographic period was much lower than that in another group of 30 consecutive patients with acute myocardial infarction. In 10 patients (group 3) who had the same procedure as groups 1 and 2 except without the selective coronary arteriography, the serum enzyme levels showed no noticeable increase after the procedure. The difference in postangiographic serum CK elevation between patients with and without selective coronary arteriography and the difference between group 1 (without significant coronory narrowing) and group 2 (with significant narrowing) strongly suggest that the raised serum CK levels represent some form of myocardial damage caused by the coronary arteriography, which, however, is different at least in degree from that of acute myocardial infarction.

Adult↗
PubMed1976

Studies on biological functions of 5'-methylthioadenosine vitamin B12-replacing effect for Ochromonas malhamensis.

An unidentified factor which can completely replace the vitamin B12 requirement of a protozoan, Ochromonas malhamensis, was found in commercial yeast extract powder. The factor showed a positive sugar test with orcinol reagent. The presence of sulfur was demonstrated with platinic iodide reagent. The molecular weight, 297, and the chemical formula, C11H15O3N5S, were determined by mass spectrometry and elemental analysis. Infra-red and nuclear magnetic resonance studies indicated the presence of a thiomethyl group. The factor was hydrolyzed by treatment with acid into adenine and 5-methylthioribose, i.e., the sugar constituent of 5'-methylthioadenosine. The factor was identified as 5'-methylthioadenosine from the behavior exhibited in thin-layer chromatography and from microbiological tests for its vitamin B12-replacing effect.

Adenosine↗