Is glycogen the source of acids developed in autolysis?

Abstract

In the following communication, an attempt is made to answer the question whether glycogen contributes to the rise in acidity in an autolyzing digest.

Method.—Beef liver from the butcher was ground in sand, diluted with Ringer's Solution to make a 20 per cent. digest by weight and divided into two portions, I (control) and II, to which one gram of glycogen obtained from liver was added for every 250 c.c. digest. In order to follow the rate and extent of digestion, the following procedure was used: Fifty c.c. of the well-mixed digest were transferred to a 100 c.c. volumetric flask and made up to the mark with 5 per cent. trichloracetic acid. The mixture was left until precipitation was completed (4 to 12 hrs.) and then filtered. The nitrogen in 20 c.c. of the filtrate was then determined by Sorensen formol-titration. The reaction of medium was studied by the following method: Fifty c.c. of the digest were placed in fish-bladder dialyzing sacs and dialysis was made against Ringer's Solution for 10 hrs. Hydrogen ion concentration was then determined by the gas chain method, a Leeds and Northrup Type “K” potentiometer, Weston standard cell and platinum needle contact electrode being used. For the privilege of using the Government apparatus in the West Virginia Experiment Station, the writer thanks Professors McIlvane and Morgan.

In the following protocol, the averages of triplicate experiments are given. The rate is given in cubic centimeters of decinormal nitrogen, the hydrogen ion concentration in the Sorensen nomenclature (P_H):

At the end of the period (eleven days), the remaining glycogen, if any, was sought and it was found that 13 milligrams computed as glucose from Benedict determinations on the hydrolyzed (acid) filtrates, remained of the gram introduced, at the beginning.