Studies on the inactivation of glyceraldehyde-3-phosphate dehydrogenase by methylglyoxal

Summary Glyceraldehyde-3-P dehydrogenase (E.C. 1.2.1.12) from rabbit muscle is rapidly inactivated by methylglyoxal following pseudo first-order kinetics. Substrate, as well as inorganic phosphate, affords protection, whereas NAD⁺ is ineffective. The arginine residue implicated in the reaction is probably the anion binding site of the phosphate group of the substrate.This investigations has been supported by grants from the Consiglio Nazionale delle Ricerche of Italy.     

The mechanism of action of glyceraldehyde-3-phosphate dehydrogenase

Zusammenfassung Zur Erforschung des Wirkungsmechanismus einer komplexen Enzymreaktion vom Typus der GAPD können die mit der Wirkung dieses Enzyms verknüpften hypokatalytischen Vorgänge gewisse Anhaltspunkte geben. Als hypokatalytische Vorgänge werden die Reaktionen bezeichnet, die durch einen Teil des natürlichen aktiven Enzyms GAPD auf unspezifische Substrate ausgeübt werden. Auf Grund der Analyse einer solchen Reaktion, d. h. der Hydrolyse desp-NPA durch GAPD, wird die natürliche Funktion des Enzyms diskutiert.Während der Hydrolyse desp-NPA wird die-Aminogruppe eines Lysinrestes der GAPD spezifisch acetyliert, die möglicherweise einen Teil des Bindungsortes der GAPD bildet.Auf Grund unserer Experimente und mit Hinblick auf frühere Publikationen anderer Forscher wird ein mögliches Modell des aktiven Bereichs der GAPD vorgeschlagen.     

Genetic evidence for the tetramer structure of glyceraldehyde-3-phosphate dehydrogenase

Zusammenfassung Es wurden beiXiphophorus maculata undXiphophorus helleri zwei Isozyme von Glyceraldehyd-3-phosphat-Dehydrogenase nachgewiesen. Die biochemisch-genetischen U Untersuchungen deuten auf eine Tetrameren-Struktur.     

S → N acetyl migration in yeast glyceraldehyde-3-phosphate dehydrogenase

Zusammenfassung Nachweis, dass bei der Hefe-GAPD-katalysierten PNPA-Hydrolyse das als Zwischenprodukt gebildete S-Acetyl-Enzym durch eine intramolekulare Wanderung zu einem N-Acetyl-Derivat führen kann. Im Gegensatz zu dem aus Muskel isolierten Enzym findet im Hefe-Enzym eine Acetylwanderung bzw. eine Acetylierung des gegebenen Lysin statt, ohne wesentliche Beeinflussung durch das Coenzym (NAD).     

Interaction of 1-anilino-8-naphthalene sulfonate with yeast glyceraldehyde-3-phosphate dehydrogenase

1--8- () -3- () . []:[]<10:1 140 000 3±1 5×10^–5 . , i 5×10^–5 –6×10^–5 M. , .     

The time course of plasma enzyme changes accompanying skeletal muscle stimulation

Summary 30 min electrical stimulation of hind limb skeletal muscle in nembutal anaesthetised dogs was accompanied by increases in arterial haematocrit, plasma GOT and plasma LDH, which were almost completed within the first 10 min of stimulation. This fast response indicated that a rapid change in either the entry and/or clearance of enzyme from the plasma must have occurred.     

Selective and reversible modification of essential thiol groups of D-glyceraldehyde-3-phosphate dehydrogenase by isothiocyanates

Summary Aralkyl and alkyl isothiocyanates, like aryl isothiocyanates, undergo a selective and reversible reaction with essential thiol groups of D-glyceraldehyde-3-phosphate dehydrogenase; the former 2 substances require for a reversible reaction course a more alkaline medium and presence of a thiol.The authors are indebted to Dr J. Augustín for valuable discussions, to Dr E. Rená and Dr M. Gemeinerová for their technical assistence. The authors wish also to thank Dr H. R. Kricheldorf for sample of 4-(trimethylsilyl) butanoyl isothiocyanate     

Selective and reversible modification of essential thiol groups of D-glyceraldehyde-3-phosphate dehydrogenase by isothiocyanates.

Aralkyl isothiocyanates, like aryl isothiocyanates, undergo a selective and reversible reaction with essential thiol groups of D-glyceraldehyde-3-phosphate dehydrogenase; the former 2 substances require for a reversible reaction course of more alkaline medium and presence of a thiol.     

Glucose-6-phosphate dehydrogenase of rat liver peroxisomes

Summary A study was made of the effect of chronic administration of clofibrate on the activity and intracellular localization of rat liver glucose-6-phosphate dehydrogenase. Clofibrate-activated glucose-6-phosphate dehydrogenase was found to be located in peroxisomes.     

Single amino acid substitutions in sn-glycerol-3-phosphate dehydrogenase allozymes from Drosophila virilis

The amino acid sequence was compared among the three allelic variants (allozymes) of sn-glycerol-3-phosphate dehydrogenase in D. virilis, which are detected by one-dimensional electrophoresis. The alpha GPDHf variant was different from the alpha GPDHm by only one substitution of 68-lysine for asparagine; alpha GPDHs differed from alpha GPDHm by substitution of 127-glycine for arginine. No electrophoretically 'silent' substitutions were found in a total of 352 amino acid residues.     

Toxicity of statins on rat skeletal muscle mitochondria

We investigated mitochondrial toxicity of four lipophilic stains (cerivastatin, fluvastatin, atorvastatin, simvastatin) and one hydrophilic statin (pravastatin). In L6 cells (rat skeletal muscle cell line), the four lipophilic statins (100 micromol/l) induced death in 27-49% of the cells. Pravastatin was not toxic up to 1 mmol/l. Cerivastatin, fluvastatin and atorvastatin (100 micromol/l) decreased the mitochondrial membrane potential by 49-65%, whereas simvastatin and pravastatin were less toxic. In isolated rat skeletal muscle mitochondria, all statins, except pravastatin, decreased glutamate-driven state 3 respiration and respiratory control ratio. Beta-oxidation was decreased by 88-96% in the presence of 100 micromol/l of the lipophilic statins, but only at higher concentrations by pravastatin. Mitochondrial swelling, cytochrome c release and DNA fragmentation was induced in L6 cells by the four lipophilic statins, but not by pravastatin. Lipophilic statins impair the function of skeletal muscle mitochondria, whereas the hydrophilic pravastatin is significantly less toxic.     

Comparison of the protein constituents of sarcoplasmic reticulum isolated from rat skeletal and cardiac muscle

Zusammenfassung Die Protein-Zusammensetzung des sarcoplasmatischen Reticulums vom Herzmuskel wurde mittels Polyacrylamid-Gel-Elektrophorese untersucht und ihr Unterschied in der hauptsächlichen Proteinkomponente zum Skelettmuskel SR gefunden.

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Supported by a research studentship from the Science Research Council.

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Supported by a research assistantship from the Science Research Council.