scholarly journals Lactic Acid, Pyruvic Acid, Amino Acids, Acetone Bodies, Oxygen, Carbon Dioxide, and Hemoglobin in Arterial and Mammary Venous Bloods of Cows under Various Physiological Conditions

1946 ◽  
Vol 29 (4) ◽  
pp. 183-197 ◽  
Author(s):  
J.C. Shaw
1956 ◽  
Vol 34 (1) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.


1929 ◽  
Vol 19 (4) ◽  
pp. 627-648 ◽  
Author(s):  
V. Subrahmanyan

(1) In absence of decomposing organic matter addition of nitrate led to no loss of nitrogen.(2) On addition of small quantities of fermentable matter such as glucose there was (a) rapid depletion of nitrates and oxygen, but no denitrification, and (b) increase in acidity, carbon dioxide and bacteria. The greater part of the soluble nitrogen was assimilated by microorganisms or otherwise converted and the greater part of the added carbohydrate was transformed into lactic, acetic and butyric acids.(3) The organic acids were formed from a variety of carbohydrates. Lactic acid was the first to be observed and appeared to be formed mainly by direct splitting of the sugar. It decomposed readily, forming acetic and butyric acids. Some acetic acid was formed by direct oxidation of lactic acid, with pyruvic acid as the intermediate product. All the acids were, on standing, converted into other forms by micro-organisms.


Author(s):  
V. M. Zhmakin

The nature of carbon, initial components, molecules of homochiral abiogenic synthesis and their preservation from decay and racemization for more than 4.5 billion years in carbonaceous chondrites has not been established. In the oxygen-free atmospheres of the nebula and early Earth, hydrogen and hydrogen-containing gases were oxidized with carbon monoxide and carbon dioxide to form carbon and water, as well as the intermediates of these reactions, formaldehyde and methane acid. Together with ammonia, they were the initial components of organic synthesis. According to the Rebinder rule, carbon adsorbs hydrogen well, including in organic molecules. In this connection, experiments with the assumed conditions of the early Earth were carried out by adsorption on carbon to obtain R-(rectus, Latin) ribose from formaldehyde, and S-(sinister) serine from formaldehyde, methane acid and ammonia. For other S-amino acids, a stereo chemical justification of their formation based on S-serine is given. For carbonaceous chondrites, the results of the above experiments were confirmed by the correlation of an increase in homochiral excess with an increase in the amount of hydrogen in aldonic acids and lactic acid with a coefficient of 0.94 and 0.85 in amino acids. The justification of the homochiral process will reduce the costs of searching for life on planets, for scientific research, for the production of medicines, perfumes, food, and so on. Doubts about the extraterrestrial origin of homochiral enantiomers in carbonaceous chondrites arise most often due to a lack of understanding of the reasons for their appearance. This work will significantly reduce such skepticism.


1956 ◽  
Vol 34 (3) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.


1953 ◽  
Vol 141 (904) ◽  
pp. 321-337 ◽  

Barker A Saifl (1953 b ), suggested that the initial rapid increase and the subsequent slower decrease in the CO 2 output of potatoes in air after a peroid under anaerobic conditions might be partly related to a quick formation of pyruvic acid from the accumulated lactic acid and to the respiration of the Pyruvic acid via krebs cycle (krebs & johnson 1937; krebs 1952). Information bearing on the associated changes in pyruvic and α-ketoglutaric acid has now been obtained using a technique (Friedemann & Haugen 1943; Friedemann 1950) which while not fully specific gives values that are known to include true pyruvic acid and true α-ketoglutaric acid as well as non-pyruvic and non-α-ketoglutaric acid material respectively. Associated with the loss of Lactic acid in air after nitrogen and the accompanying increase followed by a decrease in the CO 2 output, Mentioned above, there was first a rapid increase in the content of 'pyruvic' and 'α-ketoglutaric acid' and then a prolonged decrease in these fractions. The analysis of the interrelation between the loss of lactic acid and the production of CO 2 and of the keto-acids, and between the changes in the rate of CO2 output and the changes in the concentration of the keto-acids and of sucrose, is taken up in the next paper in this series (Barker & Mapson 1953).


Data, presented in part I of this communication, for the changes in air and in nitrogen in the rate of CO 2 production by potato tubers and in the contents of sugar, lactic acid, alcohol and other constituents, are analyzed and discussed. Certain features of the results indicate that in nitrogen a system producing lactic acid may be competing with systems in which either CO 2 or CO 2 and alcohol are formed, for a glycolytic intermediate, possibly pyruvic acid. Stoklasa (1904) observed the formation of lactic acid, together with a considerable amount of alcohol, in potatoes during anaerobiosis. In contrast, Kostytschew (1913) found no alcohol in low-sugar potatoes under anaerobic conditions, but a little alcohol in tubers of high sugar content. In our experiments, also with low-sugar potatoes, lactic acid but no alcohol was formed in the first phase of anaerobiosis; subsequently alcohol was produced in addition to lactic acid. Thus the results of previous workers are to a certain extent reconciled by the present study. When account is taken of the formation, under anaerobic conditions, of lactic acid and alcohol, as well as of CO 2 , a marked Pasteur effect is shown. The doubts expressed by Choudhury (1939) and Boswell & Whiting (1940), based solely on observations of CO 2 output, as to the existence of a Pasteur effect in potatoes are thus seen to be unjustified.


1945 ◽  
Vol 23b (1) ◽  
pp. 1-9 ◽  
Author(s):  
G. A. Adams ◽  
R. Y. Stanier

Carbon balances have been obtained for the fermentation of glucose, xylose, pyruvic acid, and mannitol by Aerobacillus polymyxa. The chief products from glucose are 2,3-butanediol, ethanol, carbon dioxide, and hydrogen; in addition small amounts of acetic acid and acetoin are formed. In glucose fermentations under the conditions used the butanediol: ethanol ratio is about 1:1. The products of xylose fermentation are very similar, although the butanediol: ethanol ratio is shifted in favour of ethanol. From pyruvic acid the chief end-products are acetoin, acetic acid, carbon dioxide and hydrogen with almost no butanediol and ethanol production. In the fermentation of mannitol a large amount of lactic acid is produced, while butanediol production is markedly decreased, the butanediol: ethanol ratio being 1:7.


Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 106
Author(s):  
Joana N. Martins ◽  
João Carlos Lima ◽  
Nuno Basílio

To this day, the recognition and high affinity binding of biomolecules in water by synthetic receptors remains challenging, while the necessity for systems for their sensing, transport and modulation persists. This problematic is prevalent for the recognition of peptides, which not only have key roles in many biochemical pathways, as well as having pharmacological and biotechnological applications, but also frequently serve as models for the study of proteins. Taking inspiration in nature and on the interactions that occur between several receptors and peptide sequences, many researchers have developed and applied a variety of different synthetic receptors, as is the case of macrocyclic compounds, molecular imprinted polymers, organometallic cages, among others, to bind amino acids, small peptides and proteins. In this critical review, we present and discuss selected examples of synthetic receptors for amino acids and peptides, with a greater focus on supramolecular receptors, which show great promise for the selective recognition of these biomolecules in physiological conditions. We decided to focus preferentially on small synthetic receptors (leaving out of this review high molecular weight polymeric systems) for which more detailed and accurate molecular level information regarding the main structural and thermodynamic features of the receptor biomolecule assemblies is available.


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