Studies on the metabolism of pyruvic acid in normal and vitamin B1-deficient states

Abstract

THE results of in vitro work have led to the postulation of several possible paths of pyruvate removal in animal tissues; namely (1) the scheme of Toenniessen & Brinkmann [1930] whereby 2 mol. of pyruvic acid are reduced to form 1 mol. of succinic acid, and the latter is then converted,successively into fumaric, malic, oxaloacetic and 1 mol. of pyruvic acid, (2) the scheme of Krebs & Johnson [1937] whereby the oxidation of pyruvate is preceded by an anaerobic change; 2 mol. of pyruvate interact to form 1 mol. each of lactic acid, acetic acid and C02, (3) the oxido-reduction between pyruvate and an aldehyde, such as triosephosphate, giving lactic acid and an acid such as phosphoglyceric acid, (4) a direct oxidation Jike that which exists in the brain [Peters, 1936; 1938; Ochoa & Peters, 1938]. It is also relevant that according to Weil-Malherbe [1937] pyruvic acid is removed more effectively from brain slices in the presence of glucose than in its absence. However, little is known about pyruvic acid metabolism in vivo. The object of the following experiments is to throw some light on these questions. Rabbits were used in most of the experiments. Instead of estimating the changes following administration of pyruvate in the blood, urine or excreta after some time, it was decided to load the rabbit suddenly with a definite amount of pyruvate by intravenous injection lasting for 1-2 min. and study the chemical changes resulting from this immediately after the injection, a few minutes later and in some instances 35 min. later, when the blood pyruvate level had returned to the pre-injection level. Experimental details All the rabbits were kept under resting conditions for at least 1 hr. before use, as previously described. Anaesthesia was begun by first giving a sedative dose of "Numal Roche" (1 ml. of 10 % solution per kg. body weight) and com

A great adventure: From quantitative metabolism to the revelation of Chinese science

“…Given that Scheele had isolated lactic acid in 1780 and by 1835 Berzelius had purified pyruvic acid, it seems scarcely credible that, well into the 20th Century, there held sway the notion that within cells 'protoplasm' represented some kind of 'giant molecule' within which chemical events occurred that were not susceptible to dissection and analysis. Hopkins had been a resolute opponent of this view from the earliest stages of his career and he was convinced If the definition of 'classic' papers is that they are still being cited many decades after publication, the set of five by Lu Gwei-djen (鲁桂珍) ( Figure 1) on the metabolism of pyruvic acid that appeared in the Biochemical Journal in 1939 [1][2][3][4][5] certainly meet the criterion (cited by, e.g., de Almeida et al 6 ). In purely numerical terms, the first of these papers 1 , which defined a new method for determining the amount of pyruvate in blood, has been cited over 200 times and remains among the 50 most highly cited papers published in the Biochemical Journal before 1940.…”

“…Finally in this series, with Dorothy Needham, Lu investigated the fate of pyruvate in vivo by injecting it into rabbits and showing that blood lactate levels rose significantly, leading them to suggest that the reaction was important in the rebuilding of carbohydrate, reflected in the subsequent increase in glucose 5 .…”

“…These breathtaking advances would doubtless have amazed and delighted Lu, who, in a different world, took the intrepid step of leaving Shanghai for Cambridge to work with Joseph and Dorothy Needham, a story that has been told in fascinating detail elsewhere 15 . Altogether, Lu published only eight research papers, the last in 1941 [1][2][3][4][5]10,16,17 . However, five further papers written jointly with [18][19][20][21][22] reflect the fact that she became Needham's muse and essentially devoted the rest of her life to him and to the realization of the incredible series of 24 volumes that comprise Science and Civilisation in China to date.…”

The Formation of Pyruvic Acid in Barley Respiration

“…N NaOH in water). According to Lu (1939), colours given by some similar compounds fade rapidly. The hydrazone of a-ketoglutaric acid (M.P.…”