Studies on the Chemistry of the Living Bark of the Black Locust Tree in Relation to Frost. VI. Amylase and Phosphorylase Systems of the Bark Tissues

Abstract

Wlhile studying the relation of the chemical composition of the living bark of the black locust tree (Robinia pseuidoacacia) to its frost resistance, 26,27) have observed marked seasonal fluctuations in the starch and sucrose contents of this tissue. The analytical data were suggestive of the existence of a temperature-sensitive starch-sucrose interconversion process, low temperature in late fall promoting a disappearance of starch and warm temiiperature of early spring promoting the production of starch with a proportionate and simiultaneous disappearance of sucrose. Because of the pronounced seasonal changes in the nature of the carbohydrate reserves in the black locust tree bark it was of interest to study enzyme systems which m-iight be involved. Further interest was attached to such a study because little information concerning the enzyme systems present in the living bark of trees is available. The presence of amylase and phosphorylase systems in the bark tissue of the black locust tree is established and characterization studies on these systems are presented here.The enzymilatic degradation of polysacchlarides of the starch-glycogen type miiay be hydrolytic, as catalyzed by amylases, or phosphorolytic, as catalyzed by phosphorylase. The mode of action of the amylases has been the subject of many studies and of several reviews (3,10,22,25). Two types of amnylase, a and ,8, are recognized. The a-amiiylases degrade starch preferentially by lhydrolyzing glycosidic linkages far removed from the terminal units. With prolonged incubations, however, a-amylase causes considerable conversion of starch to maltose together with the liberation of a small amount of glucose. /3-Amylase degrades starch by hydrolytic cleavage of successive imaltose units progressing from the non-reducing ends of the polysacelharide clhains. This action is stopped at the branching points of the amylopectin component of starch, but the degradation of the linear component approaches completion. The depolymerizing action of the amyl-1

Evidence of Phosphorylase Activity in Stylonychia Pustulata

“…Different optimum pH values from 5.4 to 6.4 have been reported for the enzyme from the potato tuber, the bark of the black locust, and the chloroplasts of wheat (14,4,25). Similar variations might occur in the activity of the enzyine from aniinal sources.…”

The modes of action of toxic agents: II. Factors influencing the toxicities of mercury compounds to certain Crustacea

“…Thus, in studies of the inactivation of papain (Hellerman & Perkins, 1934), urease (Hellerman, Chinard & Deitz, 1943;Evert, 1952), succinoxidase (Barron & Kalnitsky, 1947), invertase (Gemmill & Bowman, 1950), amylase and phosphorylase (Ewart, Siminovitch & Briggs, 1953) and yeast carboxylase (Stoppani, Actis, Deferrari & Gonzalez, 1953) it has been found that the inhibitory powers of mercury compounds are much less when the enzyme is protected by such compounds as BAL, cysteine, reduced glutathione and thioglycollic acid. Further, even when the enzyme has been inhibited, the addition of a sulphydryl compound to the system can restore enzymatic activity.…”

Factors affecting, and methods for measuring low temperature tolerance of alfalfa, Medicago Sativa L

“…It included four fertilizer treatments, eight al falfa varieties and two systems of cutting management. 22 Fertilizer treatments were assigned to the whole plots and included a check (P Q K 0 ), yearly applications of phosphorus at 53 pounds per acre (P]_K 0 ), yearly applications of potassium at 100 pounds per acre (P 0 K]_), and both phosphorus and potas sium at the above rates (P]_K]_).…”