Lactic Acid Formation in Muscle Extracts.

Abstract

Embden and Haymann 1 demonstrated that the addition of glycogen and sodium fluoride to freshly prepared muscle press-juice caused a very marked decrease in the inorganic phosphate which was present in the extract. Sugars were inactive in the reaction. The disappearance of the inorganic phosphate was interpreted as an esterification process in which hexose phosphate (lactacidogen) was formed. Meyerhof 2 showed that there is a production of lactic acid during the course of glycogen degradation by muscle extracts, and that the phosphates appear to take an active part in the changes involved. Fluoride caused a decrease in the production of lactic acid as well as a disappearance of the inorganic phosphates.

The fate of the added glycogen with reference to the amount of total hydrolysable carbohydrate present in the working mixtures at the end of the incubation seems not to have been studied.

In our experiments we have endeavored to balance the carbohydrate loss against the lactic acid gain, and, at the same time, form some conception of the amount of carbohydrate that took part in the esterification with phosphoric acid. Simultaneous determinations of lactic acid, free sugar, total carbohydrate, and inorganic phosphate were made at 0, 30, 60, 120, and 240 minute intervals on aliquot portions of mixtures of muscle extract and glycogen solution.

The extract was prepared from chopped rabbit muscle by mixing two parts of ice cold distilled water with one part of muscle and straining through muslin after allowing the mixture to stand onehalf hour at 0°. The animals were anesthetized with amytal, to prevent the rise of lactic acid in the muscle, by abolishing the death struggles, and killed by bleeding. The extract was used immediately after its preparation.