Pasteur Inorganic phosphate

It had been known from at least the time of Pasteur that the presence of sodium or potassium phosphate aided the progress of a yeast fermentation. Later intensive study showed that a complex group of enzymes (phosphatases and phosphorylases) was responsible for the phosphorylation, dephosphorylation and interconversion of D-glucose 6-phosphate, D-fructose 6-phosphate, D-fructose 1,6-diphosphate and similar substances in various types of cells and muscle tissue. Detailed reviews of the field are available. - A further advance was made in 1936, when Cori and Cori noted that in certain circumstances well-washed frog muscle immersed in a sodium phosphate buffer utilized the inorganic phosphate to produce a new hexose phosphate (the Cori ester). This compound was later shown to be a-D-glucopyranose-l-phosphate and yielded crystalline dipotassium and brucine salts. The Cori ester arose because... 

Alkaline phosphomonoesterase (EC 3.1.3.1). The existence of a phosphatase in milk was first recognized in 1925. Subsequently characterized as an alkaline phosphatase, it became significant when it was shown that the time-temperature combinations required for the thermal inactivation of alkaline phosphatase were slightly more severe than those required to destroy Mycobacterium tuberculosis, then the target micro-organism for pasteurization. The enzyme is readily assayed, and a test procedure based on alkaline phosphatase inactivation was developed for routine quality control of milk pasteurization. Several major modifications of the test have been developed. The usual substrates are phenyl phosphate, p-nitrophenyl-phosphate or phenolphthalein phosphate which are hydrolysed to inorganic phosphate and phenol, p-nitrophenol or phenolphthalein, respectively ... 

This phenomenon, which is known as the Pasteur effect, has been attributed to several mechanisms (Barnett and Entian 2005). Respiration needs very high amounts of ADP inside the mitochondria as a subtract for oxidative phosphorylation. Therefore, when respiration takes place, the cytoplasm lacks ADP and inorganic phosphate (Lagunas and Gancedo 1983), which in turn decreases the sugar transport inside the cell (Lagunas et al. 1982). These mechanisms explain how aeration inhibits the alcoholic fermentation. 

Phosphofructokinase (EC 2.7.1.30) catalyses the phosphorylation of fructose-6-phosphate to fructose-1,6-biphosphate as the key regulatory enzyme of glycolysis. Inhibition of phosphofructokinase by adenosine triphosphate and its activation by adenosine monophosphate and inorganic phosphate is held responsible for the induction of the Pasteur effect (for review see Ramaiah 1974). 

In 1941 Feodor Lynen in Munich and Marvin Johnson in Madison independently made the most significant proposal among the early attempts to account for the Pasteur effect. They proposed the theory that in aerobiosis there was a lack of phosphate because of the efficient competition of oxidative phosphorylation for the inorganic phosphate required for glycolysis. This phosphate competition hypothesis has been most vigorously championed by Racker. A related alternative possibility, competition for the nucleotide phosphate acceptor, was implicit in Johnson s paper, explicitly formulated simultaneously by Fritz Lipmann and vigorously supported by Britton Chance on the basis of the great affinity of the oxidative phosphorylation for ADP. 

Some have attempted to explain the Pasteur effect on the basis of concentration changes of inorganic phosphate and ATP others have postulated a direct influence on the enzymes. So far, the question remains unsolved. 

After removal of the toluene, the mixture was pasteurized at 80° for 5 minutes, cooled, adjusted to pH 7.8 and 2.5 volumes of 95% alcohol added. The mixture was allowed to remain at 4° for 3 hours and the precipitate, containing most of the inorganic and esterified phosphate, was removed by filtration and the alcohol was removed by distillation in vacuo at about 30°. The solution was then made up to 600 ml. and passed through columns of Amberlite IR-100 and Amberlite IR-4. This treatment removed all the electrolytes, including the remaining traces of n-glucose-l-phosphate. After washing the columns with water, the volume had increased to about three liters. The solution was concen-... 

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