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S Muto

Publications and source records attributed to S Muto.

At least 181 records · Page 10Linked to original sources
PubMed1981

Light-induced conversion of nicotinamide adenine dinucleotide to nicotinamide adenine dinucleotide phosphate in higher plant leaves.

Light-induced conversion of NAD to NADP was investigated in higher plants. Upon illumination, conversion of NAD to NADP was observed in intact leaves of wheat and pea following incubation in the dark. This conversion was also observed in mesophyll protoplasts of wheat leaves when they were isolated in the dark or isolated in light and then preincubated in the dark. Chloroplasts isolated from wheat protoplasts prepared in the dark carried out the conversion. The conversion in the mechanically isolated spinach chloroplasts was observed only when they were isolated in the dark from leaves preincubated in darkness.Sucrose density gradient centrifugation of wheat protoplast extracts and differential centrifugation of protoplast extracts from various plants showed that most of the NAD kinase was localized in the chloroplasts. Therefore, the conversion of NAD to NADP is considered to occur in the chloroplasts. However, with extracts of maize mesophyll protoplasts, the enzyme was localized in the extrachloroplast fraction. The NAD kinase was activated some 30% by illumination of leaves or protoplasts of pea and wheat after preincubation in the dark.These results suggest that, in general, the light-induced conversion of NAD to NADP occurs in the chloroplast and is catalyzed by photoactivated NAD kinase using photochemically produced ATP.

Journal Article↗
PubMed1977

Properties of a Protein Activator of NAD Kinase from Plants.

Purification of pea (Pisum sativum) seedling NAD kinase by DEAE-cellulose column chromatography resulted in loss of activity, due to dissociation of an activator from the enzyme. The purified enzyme preparation, which was almost completely inactive, regained the activity when the activator was added back.The activator was purified 320-fold by ion exchange chromatographies. The activator was susceptible to proteolytic enzymes, but not to ribonuclease, glucoamylase or pectinase, indicating that it is of a protein nature. This protein was relatively stable in boiling water, but susceptible to acid or alkali, especially under high temperatures. Restoration of catalytic activity of inactive enzyme was proportional to amounts of the activator added. Gel filtration indicated that molecular weight of the activator was 28,000.The activator was found in extracts from various plants.

Journal Article↗
PubMed1974

Lipase Activities in Castor Bean Endosperm during Germination.

Two lipases were found in extracts from castor bean (Ricinus communis L.) endosperm. One, with optimal activity at pH 5.0 (acid lipase), was present in dry seeds and displayed high activity during the first 2 days of germination. The second, with an alkaline pH optimum (alkaline lipase), was particularly active during days 3 to 5. When total homogenates of endosperm were fractionated into fat layer, supernatant, and particulate fractions, the acid lipase was recovered in the fat layer, and the alkaline lipase was located primarily in the particulate fraction. Sucrose density gradient centrifugation showed that the alkaline lipase was located mainly in glyoxysomes, with some 30% of the activity in the endoplasmic reticulum. When glyoxysomes were broken by osmotic shock and exposed to KCl, which solubilizes most of the enzymes, the alkaline lipase remained particulate and was recovered with the glyoxysomal "ghosts" at equilibrium density 1.21 g/cm(3) on the sucrose gradient. Association of the lipase with the gly-oxysomal membrane was supported by the responses to detergents and to butanol. The alkaline lipase hydrolyzed only monosubstituted glycerols. The roles of the two lipases in lipid utilization during germination of castor bean are discussed.

Journal Article↗
PubMed1966

[Neurogenesis].

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Animals↗
PubMedDate not supplied

Effect of plasmapheresis as initial monotherapy in a case of anti-neutrophil cytoplasmic autoantibody positive crescentic glomerulonephritis.

The effect of plasmapheresis (PP) monotherapy was evaluated in a 77 year old man with crescentic glomerulonephritis (CrGN). Because both anti-neutrophil cytoplasmic myeloperoxidase autoantibody (MPO-ANCA) and circulating immune complex (IC) were positive, removal of these substances was expected to be beneficial. Thus, the treatment was started with PP alone. During 2 month's time, three series of PP monotherapy were performed: three sessions of plasma exchange (PEX) with fresh frozen plasma (FFP); two sessions of double filtration plasmapheresis (DFPP); followed by another two sessions of PEX. The ANCA remained suppressed for 4 weeks after the first PEX, and increased thereafter. Subsequent DFPP caused a rebound in ANCA titer, whereas the second PEX suppressed ANCA for 1 week. Although creatinine clearance (Ccr) improved from 9.3 to 15 ml/min after the first PEX, and this level was maintained, ANCA increased again after the second PEX. Therefore, the patient was treated with methylprednisolone semi-pulse therapy (500 mg/day for 3 days), followed by mild "cocktail" therapy. In 2 weeks ANCA and IC became negative, and Ccr further improved to 20 ml/min. Thus, PP, when performed alone, was shown to be partially effective, arresting the progression of renal damage in the present case. These observations also argue for the advantage of PP, especially PEX, as an adjunct therapy to immunosuppressive therapy in CrGN.

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