[64] Chromatographic analyses of organic acids

Varner, J. E.

doi:10.1016/s0076-6879(57)03404-7

Cited by 48 publications

(21 citation statements)

References 5 publications

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“…The specific activities of lactate isolated [5] from perfusate and extract (not corrected for perfusate contamination) were indistinguishable. Pyruvate specific activities, on the other hand, were very different: for example in 5 non-hormonetreated hearts the extract specific activity was 100 & 14 dis.…”

Section: Redistribution Of Label In Lactate and Pyruvatementioning

confidence: 92%

See 1 more Smart Citation

The Effect of Insulin and Growth Hormone on the Flux of Tracer from Labelled Lactate in Perfused Rat Heart

Mowbray

Ottaway

1973

European Journal of Biochemistry

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~[2-14C]Lactate tracer was added at 30 min to the perfused rat-heart preparation described in the previous paper. The specific activities of perfusate and tissue lactate and pyruvate were measured over the period up to 60 min.2. Perfusate and heart lactate radioactivity equilibrated rapidly : not so perfusate and heart pyruvate.3. No pyruvate was lost from the tissue: the sole precursor of perfusate pyruvate was lactate. I n the presence of insulin all pyruvate taken up from perfusate was obligatorily reduced to lactate.4. A proportion of pyruvate in the heart did not become labelled and there is good reason to believe this is not an artifact. 5. Rate parameters at different steps in pyruvate metabolism have been determined by computer modelling. Both hormones modify these parameters : in particular pyruvate dehydrogenase appears to undergo rapid 7-fold activation.6. The rate of exchange of label between lactate and intracellular labelled pyruvate was used to calculate the [NAD]/[NADH] ratios in the exchange compartment and in mitochondria. Both hormones reduced the ratio about 5 times by comparison with control. The results emphasise the disparity between perfusate lactate/pyruvate ratio and the redox potential of cardiac cytoplasm.7. The data strongly support the compartmentization in more than one distinct cytoplasmic space of some glycolytic enzymes in cardiac tissue. The relationship of these "compartments?? to heart morphology is briefly discussed.8. Evidence is presented that growth hormone exerts a much greater rapid "insulin-like" effect than has hitherto been suspected.It is possible by the use of tracer to obtain a great deal of information about the organisation of and the rate parameters of enzymes affecting pyruvate metabolism in the intact beating rat heart (see also the preceding paper [l]). Steady state or, in the case of pyruvate, reproducible nonsteady state conditions have been found and the material fluxes measured [l]. Although in reversibly interconnected compartmental systems it does not matter which compartment is initially labelled [2], perfusate lactate was chosen because of its size and constancy [I].In this study of the kinetics of tracer distribution, alanine has been neglected, on the principle of perturbation [2] since its known rate of incorporation in protein is very low [3] and its accumulation

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Section: Redistribution Of Label In Lactate and Pyruvatementioning

confidence: 92%

“…Lactate and pyruvate were thus purified [5] from 60-min perfusate and subjected to stepwise degradation [lo]. I n all cases the radioactivity in carbon atoms 1 and 3 was negligible.…”

Section: Redistribution Of Label In Lactate and Pyruvatementioning

confidence: 99%

The Effect of Insulin and Growth Hormone on the Flux of Tracer from Labelled Lactate in Perfused Rat Heart

Mowbray

Ottaway

1973

European Journal of Biochemistry

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“…Each of these was further analyzed by TLC on cellulose plates using phenol-waterformic acid (75:24:1) and the organic phase of the mixture 1-butanol-formic acid-water (100:30:100) as solvents. The identity of malic, citric, succinic, and fumaric acids was confirmed using a silicic acid column according to Varner (16). Sugar phosphates in fraction III were identified by TLC according to Bandurski and Axelrod (1) and by ion exchange chromatography of their borate complexes according to Khym and Cohn (10).…”

Section: Methodsmentioning

confidence: 99%

Glucose Metabolism and Retention of Glucose Metabolites in the Wheat Embryo during Early Germination

Ginzburg¹

1978

Plant Physiol.

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There is a lag period in the growth of excised wheat (Tritkum vulgare Host.) embryos extending from 0.5 hour to 4.5 hours of their imbibition in water. During this time there is a sharp increase in the embryos' capability to retain several amino and organic acids, to synthesize cell wall components and starch, and to take up glucose. Their capability to metabolize glucose also increases by 30%. Elevation of the ATP content of 1-hour embryos by incubation in 3 mM adenosine is not sufficient to bring about these changes. These changes may be a part of a metabolic adjustment in the embryos which increases their growth potential.

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“…The synibols are: ...., ml of base/3n ml fractioll and(l , CPM/ 3 nil fractioni. (27). In otir p)roce(lure for gra(lienit eltitioni 75 nil of water-saturate(l chloroforim were l)laced in a milixilig chamber conlilected to a reservoir conitainlilng 700 ml of water-saturated n-butyl alcohol-chloroformil (60/ 40. v/v).…”

Section: Methodsmentioning

confidence: 99%