THE DECOMPOSITION OF L-(+)-TARTARATE BY THE MICROORGANISMS

[摘要] Using Pseudomonas incognita strain 3L aerobic and anaerobic decomposition of L-(+)-tartarate was investigated.Succinic and acetic acids were isolated and identified as the anaerobic decomposition products of tartarate by resting cells. Furthermore, from the balance studies it was clearly established that anaerobic decomposition of tartarate is performed according to eq. (3).In order to clarify the mechanism of this reaction, anaerobic decomposition of tartarate by resting cells was conducted in the presence of radioactive bicarbonate and the incorporation of C14O2 into various compounds was examined. From the experimental results two schemes (Scheme I and II.) were proposed to explain the observed incorporations of the isotope. But the following experimental results excluded the possibility of Scheme I as the main path of the anaerobic decomposition of tartarate by this organism.(1) D-(-)-Phosphoglycerate was decomposed anaerobically and about 1 molecule of CO2 was evolved per molecule of phosphoglycerate consumed, while 1/3 molecule of CO2 should be expected if this compound were metabolized according to Scheme I. Therefore CO2 fixation reaction according to Scheme I did not occur under these conditions. From the thermodynamic point of view, the CO2 fixation reaction according to Scheme I may be performed more easily when phosphoglycerate rather than tartarate is the substrate. Therefore this experimental result makes Scheme I unlikely.(2) Similarly succinate formation by the CO2 fixation reaction was not observed in the anaerobic decomposition of pyruvate, (3) NaF, in the final concentration of M/600, completely inhibited the decomposition of phosphoglycerate, whereas the decomposition of tartarate was not inhibited in the same concentration. Therefore phoshoglycerate was excluded as the intermediate.(4) Anaerobically, DL-glcerate was not metabolized by this organism and is not likely to be the intermediate.

[学科分类] 微生物学和免疫学