Tumor Amylase: General Properties and Estimation of Activity

A study by Salter, Meyer, and Aub (1), of the enzyme system in tumors which deals with carbohydrate metabolism, has indicated its high specificity for glucose. Among other characteristics, the inability of intact tumor cells to produce lactic acid from glycogen (derived from the same species) was noteworthy. Barr, Ronzoni, and Glaser (2), likewise using the technic of Warburg for (lactic) acid production, had previously observed the same fact. However, Buxton (3), working twenty-five years ago with various types of malignant tissue, found an amylolytic enzyme uniformly present in hashed tumors which was capable of acting on both starch and glycogen, and whose activity he was able to estimate roughly. It is the purpose of this paper to show the general properties of this enzyme and to suggest a method whereby its activity can be accurately measured. Sourceof Materials Mouse sarcoma 180 was the malignant tissue of choice because of its rapid growth and ready transplantability, and because of the cellular nature of the tumor with comparatively little, and usually localized, necrosis. This transplanted neoplasm, borne by pure strain, tumor-susceptible mice (inbred for nine years) was used throughout. The tumor was studied three to four weeks after transplantation. The mouse was killed by a blow over the head, the throat was cut, and the tumor was removed, its capsule and adherent tissue cleaned off, and the necrotic center discarded. After weighing the tumor to 0.1 gram it was ground in a small mortar with washed sand, and an equal weight of distilled water was added. Grinding and extraction were continued for from two to five minutes, after which the tumor hash was centrifuged for fifteen minutes. The supernatant fluid, designated as concentrated (50 per cent) tumor extract, was decanted. This stock extract, preserved with toluol and kept in the ice box, retains its activity essentially unaltered for several months.