Purification and properties of ornithine aminotransferase from rat brain

Summary Ornithine aminotransferase (E.C. 2.6.1.13) from rat brain was purified 100-fold by ammonium sulphate fractionation, DEAE cellulose chromatography, calcium phosphate gel and alumina C gel. Pyridoxal phosphate was essential for maximum activity of the enzyme. The brain enzyme did not differ from liver and kidney enzymes in properties such as pH optimum, K_m, substrate specificity and the inhibition by branched chain amino acids. Unlike rat liver enzyme, brain ornithine aminotransferase was able to catalyze the reaction between L-lysine and 2-oxoglutarate. Spermidine and spermine inhibited brain ornithine aminotransferase activity.Acknowledgments. D.R.D. is thankful to U.G.C., India, for the award of a fellowship under the special assistance programme. Present address: Department of Pediatrics and Communicable Diseases, F2815, Box 066, C.S. Mott Children's Hospital, University of Michigan, Ann Arbor, MI 48109, USA.     

N-(5′-Phosphopyridoxyl)-4-aminobutyric acid: a stable bisubstrate adduct inhibitor of rat brain 4-aminobutyric acid aminotransferase

Summary N-(5-Phosphopyridoxyl)-4-aminobutyric acid, a stable adduct of pyridoxal phosphate and 4-aminobutyric acid, has been shown to be a potent inhibitor of rat brain 4-aminobutyric acid aminotransferase (GABA-T) with a K_i of 1.4 M.Acknowledgments. This work was supported in part by the United Parkinson Foundation, l'Association Canadienne l'Ataxie de Friedreich, and the Medical Research Council of Canada.     

Free amino acid pattern in stressed leaves of two contrasting resistant and susceptible cultivars of chick pea (Cicer arietinum)

Summary Drought resistant cv. C-214 ofCicer arietinum L. showed higher accumulation of alanine, threonine, glutamine, -alanine, arginine, amino butyric acid, valine, leucine, phenylalanine than the susceptible cv. G130 under water stress.     

Comparison of lysine and tryptophan catabolizing enzymes in rat and bovine tissues

Summary Earlier studies indicate that -aminoadipate aminotransferase (AadAT) and kynurenine aminotransferase (KAT) activities from rat tissues are associated with a single protein. However, our recent studies indicate that AadAT activity from bovine liver and kidney is not associated with KAT activity. To test whether the lysine and tryptophan catabolism in bovine tissues differ from that in rat tissues, we compared the activities of enzymes involved in lysine and tryptophan pathways in rat and bovine tissues. The activities of lysine catabolizing enzymes such as AadAT, lysine -ketoglutarate reductase and saccharopine dehydrogenase in the bovine tissues were significantly lower than those found in rat tissues. The activities of tryptophan catabolizing enzymes such as KAT and kynurenine hydroxylase in the bovine tissues were negligible as compared to those in rat tissues. The results suggest that lysine is degraded via the saccharopine pathway in the livers and kidneys of both species but the metabolism of tryptophan in bovine tissues may be different from that in rat tissues.Acknowledgments. This work was supported by a grant from the Children's Hospital of Michigan and by a Research Career Development Award from the National Institutes of Health to D. R. Deshmukh.     

β-(6-Bromopyridin-3-yl)alanine. A new plant growth regulator

Summary The heterocyclic amino acid, -(6-bromopyridin-3-yl)alanine [DL-a-amino--(6-bromopyridin-3-yl)propanoic acid], interferes with the morphological development of the cruciferArabidopsis thaliana when incorporated in the growth medium. It appears to overcome the normal apical dominance control mechanism within the seedling, producing multirather than single-stemmed plants.     

Effect of lithium chloride on the rat's paw edema induced by serotonin,histamine and formalin

Résumé Administration parentérale de chlorure de lithium inhibe l'dème de la patte produit par l'injection locale de serotonine, histamine ou formol chez le rat normal mais non pas chez le rat surrénaléctomizé. Ces resultats suggerent que l'effect antiphlogistique du chlorure de lithium est du à une liberation de corticosteroïdes.

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I should like to thank Sandoz, Basel (Switzerland) for supplying serotonin (5-Hydroxytryptamine creatine sulfate) and Merck, AG Darmstadt, for histamine hydrochloride. The technical assistance of Mr.B. Koç and Mr.V. Balolu is greatly appreciated.     

Auswirkungen einer definierten Belastung auf die Enzymaktivitäten im Blutplasma bei der Maus Effects of a definite stress on the enzyme activities in blood plasma in mice

Summary The present study was designed to analyze the effects of a short term stress on the quantitative levels of alkaline phosphatase (AP), creatine phosphokinase (CK), aldolase (ALD), lactate dehydrogenase (LDH), and lactate dehydrogenase-1-isoenzyme (LDH 1) during 24 h after stress. For all the enzymes studied higher values for the activity were found due to stress in comparison to the activity level before the stress. The period during the 24 h after stress to reach maximum activity depends on the enzyme and in part on the sex of the animal.     

Aminoacidi della Perilinfa

Summary The following aminoacids have been detected in the perilymph from horses by filter paper chromatography: aspartic acid, glutamic acid, phosphocolamine, glycine, serine, taurine, threonine, alanine, glutamine, lysine, arginine,-aminobutyric acid, proline, valine, leucine, tyrosine, phenylalanine, cystine.A comparative study of chromatograms obtained from blood, perilymph and liquor showed that the perilymph is much more similar to the blood than to the cerebrospinal fluid either for qualitative and for quantitative content in aminoacids.     

Die Rolle von Glukose im Erholungsprozess des Muskels

Summary It is well known that after exhausting muscle work glucose (or saccharose) leads to quick recovery in man. Experiments on rats have shown that in adult animals 50% of all creatine is present as creatine-phosphate (CP). In old animals above 22 months, only about 25% is present as CP. Diets with a 50% glucose content lead in old animals, in rest, to 50% CP in the muscle. Also after exhausting work on glucose diet the restitution is so complete that about 50% CP is present. The main reservoir of energy for the restitution of muscle, ADP ATP, comes from the breakdown of CP. The problem may be discussed whether high glucose diet may be damaging insulin production by exhaustion.     

Liver function during chronic renal failure in rabbits

In rabbits with chronic renal insufficiency the prothrombin index was increased by 25% and the alanine aminotransferase activity decreased by 20%; the results of other routine tests of hepatic function were not affected. The galactose elimination capacity was decreased by 12%, whereas the body clearance of antipyrine was unchanged. No change in hepatocytic structure was found.     

Liver function during chronic renal failure in rabbits

Summary In rabbits with chronic renal insufficiency the prothrombin index was increased by 25% and the alanine aminotransferase activity decreased by 20%; the results of other routine tests of hepatic function were not affected. The galactose elimination capacity was decreased by 12%, whereas the body clearance of antipyrine was unchanged. No change in hepatocytic structure was found.     

Differential expression of isozymes in relation to organogenesis in two closely related species

Summary Two closely related species of Gentianaceae were established in tissue culture and transferred to a regeneration medium containing 2,4-D. Even though the age of cultures and all the environmental conditions were identical, only one of them expressed a clear morphogenic potential, and the differences are expressive in the isozyme banding patterns observed for creatine phosphokinase, lactate dehydrogenase and indoleacetaldehyde dehydrogenase. No differences in alkaline phosphatase isozymes were detected.This work was supported in part by the National Science Foundation (No. DCB 8 611 889) USA with a grant to the senior author.     

Effects of a definite stress on the enzyme activities in blood plasma in mice (author's transl)

The present study was designed to analyze the effects of a short term stress on the quantitative levels of alkaline phosphatase (AP), creatine phosphokinase (CK), aldolase (ALD), lactate dehydrogenase (LDH), and lactate dehydrogenase-1-isoenzyme (LDH 1) during 24 h after stress. For all the enzymes studied higher values for the activity were found due to stress in comparison to the activity level before the stress. The period during the 24 h after stress to reach maximum activity depends on the enzyme and in part on the sex of the animal.     

Locust alanine aminotransferase has subunit structure

Ion exchange and gel chromatography of locust flight muscle alanine aminotransferase showed that the cytoplasmic enzyme occurs both as monomer and tetramer, whereas mitochondrial enzyme exists mainly as a dimer.     

Serum creatine kinase in marathon runners

Serum creatine phosphokinase (CK) and CK-MB activity were determined in 21 trained runners participating in a marathon race (42.2 km). Enzyme activities immediately after the race increased two to three times compared with activities before the race. The greatest increases were found in the slowest runners, suggesting greater skeletal muscular trauma in the least trained or fit. As these are likely to include the older athletes who are also more likely to suffer acute myocardial injury during strenuous exercise, our findings assume special import in the interpretation of increased CK and CK-MB serum activities of older athletes.     

Parenteral soya bean fat emulsions potentiate the hepatotoxicity ofE. coli endotoxin in suckling rats

Summary A dose of soy bean fat emulsion which was injected i.v. in suckling rats accumulated in the cells of liver parenchyma, both in hepatocytes and in reticuloendothelial cells. Subsequent i.p. injection ofE. coli endotoxin was followed by extensive liver tissue necrosis and increased activities of serum aspartic and alanine aminotransferase. These signs of liver damage were markedly more pronounced than those observed after the administration ofE. coli endotoxin only.     

Parenteral soya bean fat emulsions potentiate the hepatotoxicity of E. coli endotoxin in suckling rats

A dose of soy bean fat emulsion which was injected i.v. in suckling rats accumulated in the cells of liver parenchyma, both in hepatocytes and in reticuloendothelial cells. Subsequent i.p. injection of E. coli endotoxin was followed by extensive liver tissue necrosis and increased activities of serum aspartic and alanine aminotransferase. These signs of liver damage were markedly more pronounced than those observed after the administration of E. coli endotoxin only.     

Serum creatine kinase in marathon runners

Summary Serum creatine phosphokinase (CK) and CK-MB activity were determined in 21 trained runners participating in a marathon race (42.2 km). Enzyme activities immediately after the race increased two to three times compared with activities before the race. The greatest increases were found in the slowest runners, suggesting greater skeletal muscular trauma in the least trained or fit. As these are likely to include the older athletes who are also more likely to suffer acute myocardial injury during strenuous exercise, our findings assume special import in the interpretation of increased CK and CK-MB serum activities of older athletes.Acknowledgments. The authors wish to thank the members and president of the Columbia Track Club for their cooperation.     

Nature and the time course of the effect of CO2 on electroretinogram (ERG) in an arachnid

Summary Electroretinogram recorded from the median eye of the scorpion, Heterometrus fulvipes before and after exposure to CO₂ indicated that the rate of recovery of b wave to pre-CO₂ level was slow and delayed as compared to a wave. b wave may therefore have a more central origin than that of a wave, which finds corroboration in the results of the depth recording in this eye with the microelectrode.The equipment was a gift from USAFOSR to Prof. T. H. Bullock and Prof. K. P. Rao, and the work was carried out at the Department of Zoology, Bangalore University. I thank Dr R. V. Krishnamoorthy and Dr A. R. Kasturi Bai.     

High-affinity binding ofβ-alanine to cerebral synaptosomes might involve glycine-receptors

Summary High-affinity, Na⁺-independent binding of -alanine to a synaptosomal fraction of rat brain was potently inhibited by glycine and by some other -amino acids, but not by taurine or GABA. This binding mechanism, which was also sensitive to both bicuculline and strychnine, might involve synaptic receptors for both -alanine and glycine.This study was supported in part by Centro Ramón y Cajal and Fundacion Juan March.