The activity of alpha-amylase, glucoamylase, maltase, trehalase, glycogen phosphorylase and trehalose phosphorylase was measured in extracts from larval and adult Hysterothylacium aduncum (Rudolphi, 1802), parasitic nematode of marine fish. The content of glycogen and trehalose in the worm's body was also determined. Both the hydrolytic and phosphorolytic paths of sugar decomposition are presen...

Paretsky, D. (University of Kansas, Lawrence), C. M. Downs, and C. W. Salmon. Some biochemical changes in the guinea pig during infection with Coxiella burnetii. J. Bacteriol. 88:137-142. 1964.-Guinea pigs infected with Coxiella burnetii, the rickettsial agent of Q fever, were studied for 11 days postinfection. Maximal changes in liver lipids, liver phosphorylase, and uridine diphosphate glucos...

Addition of micromolar concentrations of the adenosine derivative 5-iodotubercidin (Itu) initiates glycogen synthesis in isolated hepatocytes by causing inactivation of phosphorylase and activation of glycogen synthase [Flückiger-Isler and Walter (1993) Biochem. J. 292, 85-91]. We report here that Itu also antagonizes the effects of saturating concentrations of glucagon and vasopressin on these...

The steady-state kinetics of the reaction catalyzed by glycogen phosphorylase b from rabbit skeletal muscles has been studied in a wide range of the concentrations of adenosine 5 ′ -monophosphate in the direction of glycogen synthesis under the conditions of saturation of the enzyme by glycogen. The kinetic model has been proposed to describe the bell-shaped dependence of the initial rate of th...

1. Livers from gsd/gsd rats, which do not express phosphorylase kinase activity, also contain much less particulate type-1 protein phosphatases. In comparison with normal Wistar rats, the glycogen/microsomal fraction contained 75% less glycogen-synthase phosphatase and 60% less phosphorylase phosphatase activity. This was largely due to a lower amount of the type-1 catalytic subunit in the part...

The regulation of enzymatic activity of several enzymes involved in glycogen breakdown has been investigated in a skeletal muscle fraction containing a protein-glycogen complex and elements of the sarcoplasmic reticulum. In this fraction, phosphorylase is entirely in its inactive b form since phosphorylase kinase itself is totally inactive while phosphorylase phosphatase is fully active. Additi...

Using cytofluorimetric and biochemical methods, the content of glycogen and its labile and stable fractions, as well as activities of glucose-6-phosphatase (EC 3.1.3.9), glycogen phosphorylase (EC 2.4.1.1) and glycogen synthase (EC 2.4.1.11) were determined in the rat liver for 6 months after chronic poisoning of the animals with CCl4 and then at 1, 3, and 6 months after the end of the poisonin...

In mammalian eggs, glycogen may well play an important role as an energy source during cleavage. Although the presence of glycogen in rat and rabbit eggs and the fluctuation of its concentration during development have been reported (ISHIDA 1954, 1963), histochemical demonstration of enzymes related to glycogen metabolism has not yet been published. Studies of glycogen metabolism are generally ...

1. Rat liver glycogen was separated into fractions of relatively uniform particle sizes by large volume rate-zonal centrifugation of tissue homogenates with the use of sucrose density gradients. 2. After centrifugation, the distribution curve obtained by plotting the glycogen content of all collected fractions exhibited its maximum a short centrifugal distance from the zone which contained the ...

Glycogen metabolism is considered to be regulated by the activities of the a forms of glycogen synthase and phosphorylase. Among other factors, the concentration of circulating blood glucose controls the activities of these two enzymes. It has been shown in experiments in oivo (De Wulf & Hers, 1967; Stalmans et al., 1974), isolated perfused liver (Buschiazzo et al., 1970; Glinsmann et al., 1970...