Since the classical discovery of Warburg (1) that fertilization of sea urchin eggs produces a sudden increase in the oxygen uptake, numerous investigators have attempted to correlate this increase to chemical changes. Perlzweig and Barron (2) found that the eggs of Arbacia punctulata contain carbohydrates and produce lactic acid. However, no increase in lactic acid formation was detected on fertilization. In 1933, RunnstrSm (3) found that 'during fertilization there is an increase in the formation of acid, the nature of which is still unknown. In 1935, ~3rstrtim (4) reported an increase in ammonia formation, which he attributed to the degradation of purines (5). This ammonia formfftion, in the opinion of Hutchens et al. (6) may be due to protein oxidation; i.e., oxidative deamination. An increased utilization of glycogen was demonstrated by 0rstrSm and Lindberg (7) and by Lindberg (8). A change in the solubility in ether and alcohol of lecithin and cephalin has also been noted: before fertilization all the cephalin is soluble in ether while after fertilization it becomes insoluble (9). Fertilization and membrane formation are essentially anaerobic processes since they can be obtained in the absence of oxygen while nuclear changes and cell division are essentially aerobic processes since they do not occur in the absence of oxygen (10). After fertilization there are an increased permeability of the cell membrane, and a channeling of oxidations via the cytochrome pathway, as shown by the inhibition of respiration of fertilized eggs by HCN and CO in contrast with the insensitivity of the unfertilized eggs to these agents (11). The increased oxygen consumption, added to an increased utilization of glycogen with the formation of an acid is an indication that during the fertilization process there is an increase of the oxidative phase of carbohydrate metabolism. Since the metabolism of carbohydrate in Arbacia eggs under anaerobic conditions ends with the formation of lactic acid, it is reasonable to conclude that the lactic acid comes from the reduction of pyruvic acid. (Arbacia eggs contain from 250 to 500 micrograms of diphosphopyridine nucleotide, the coenzyme for glycolysis, according to Jandorf and Krahl (12).) Hence, the oxidative phase must start either with the oxidation of pyruvic to acetic acid or with its carboxylation to oxaloacetic * An abstract of this work appeared in
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