Search results for "Glycogen Phosphorylase"

Flying insects: model systems in exercise physiology

1996

Insect flight is the most energy-demanding exercise known. It requires very effective coupling of adenosine triphosphate (ATP) hydrolysis and regeneration in the working flight muscles.31P nuclear magnetic resonance (NMR) spectroscopy of locust flight muscle in vivo has shown that flight causes only a small decrease in the content of ATP, whereas the free concentrations of inorganic phosphate (P i ), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) were estimated to increase by about 3-, 5- and 27-fold, respectively. These metabolites are potent activators of glycogen phosphorylase and phosphofructokinase (PFK). Activation of glycolysis by AMP and P i is reinforced synergistica…

Glycogen phosphorylase BB in acute coronary syndromes

2005

AbstractThe diagnosis of myocardial damage is preferably based on measurement of the cardiac-specific troponins. However, there is an emerging need for early, specific cardiac markers. One potential candidate is the glycogen phosphorylase BB isoenzyme (GPBB). We investigated the use of a new, commercially available GPBB ELISA assay in 61 patients presenting with an acute coronary syndrome (37 acute myocardial infarction, 24 unstable angina pectoris) in comparison to established cardiac markers such as troponin T, creatine kinase isoenzyme MB (CKMB) mass, and myoglobin. Blood samples were obtained on arrival, as well as 1, 2, 3, 4, 8, 12 and 24h later. GPBB plasma concentrations were elevate…

Skeletal muscle fibre types, enzyme activities and physical performance in young males and females

1978

Differences in skeletal muscle characteristics, metabolic profiles and functional performance between males and females were investigated using young (15--24 yrs) male and female twins as subjects. The comparison included such variables as anthropometry, muscle strength, mechanical power, maximum oxygen uptake, electrical activation of muscle, muscle fibre composition (m. vastus lateralis), and activities of several skeletal muscle enzymes. The results disclosed the following primary differences between males and females: In the various functional tests the performance of females was from 61.1 to 84.6% of that in males; distribution of slow twitch fibres in m. vastus lateralis of the female…

Glycogen phosphorylase in fish muscle: demonstration of three interconvertible forms

1990

White skeletal muscle of crucian carp contains a single isoenzyme of glycogen phosphorylase, which was purified approximately 300-fold to a specific activity of approximately 13 mumol.min-1.mg protein-1 (assayed in the direction of glycogen breakdown at 25 degrees C). Tissue extracts of crucian muscle produced three distinct peaks of phosphorylase activity when separated on DEAE-Sephacel. Peaks 1 and 3 were identified, in terms of kinetic properties and by interconversion experiments, as phosphorylase b and a, respectively. Peak 2 was shown to be a phospho-dephospho hybrid. The three interconvertible forms of phosphorylase were purified and shown to be dimeric molecules at 20 degrees C. At …

Glycogen phosphorylase from flight muscle of the hawk moth, Manduca sexta: purification and properties of three interconvertible forms and the effect…

1994

Glycogen phosphorylase (EC 2.4.1.1) of Manduca sexta flight muscle was separated into three distinct peaks of activity on diethylaminoethyl-Sephacel. The three fractions of phosphorylase activity were further purified by affinity chromatography on AMP-Sepharose and shown to have the same relative molecular mass (=178000) on polyacrylamide gradient gel electrophoresis under non-denaturating conditions and to produce subunits of molecular mass =92000 on SDS gelelectrophoresis. On the basis of their kinetic properties with respect to the activator AMP and the inhibitor caffeine, the three fractions of phosphorylase activity were assigned as follows: peak 1=phosphorylase b (unphosphorylated for…

Effects of waterborne iron overload and simulated winter conditions on acute physiological stress response of whitefish, Coregonus lavaretus

2003

Two-year-old whitefish (Coregonus lavaretus) were exposed for 30 days to episodic iron overload in iron-rich humic water (5%) supplemented with inorganic iron (5 mg FeL(-1)). Two parallel laboratory exposures were performed, one under conditions simulating winter and the other under conditions simulating spring. After exposure, some of the fish were subjected to acute handling stress in the form of a short air challenge to reveal possible modification of the primary and secondary stress responses. In whitefish sampled without additional handling, iron accumulated in the liver (under spring conditions) and gills (under winter and spring conditions); plasma catecholamine and beta-estradiol (b…

Glycogen phosphorylase in fish brain (Carassius carassius) during hypoxia

1988

Enzyme histochemical and immunohistochemical characterization of oval and parenchymal cells proliferating in livers of rats fed a choline-deficient/D…

1991

Male outbred Sprague-Dawley rats were fed a choline-deficient diet containing 0.10% DL-ethionine for up to 30 weeks. Liver slices from rats killed 4, 6, 10, 14, 22 and 30 weeks after starting the treatment were histochemically analyzed for the following parameters: basophilia, expression of cytokeratin 19 (which in the liver is bile duct epithelial cell-specific), glycogen content and activities of glycogen synthetase (SYN), glycogen phosphorylase (PHO), glucose-6-phosphatase (G6PASE), glucose-6-phosphate dehydrogenase (G6PDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerin-3-phosphate dehydrogenase (G3PDH), 'malic enzyme' (MDH), alkaline phosphatase (ALKPASE) and gamma-glutamyl…

A novel compound heterozygous mutation in PYGM gene associated with McArdle’s disease

2022

McArdle's disease is an autosomal recessive glycogenosis due to mutation in the myophosphorylase gene (PYGM) resulting in a pure myopathy. The clinical onset typically occurs in childhood with cramps, myalgia, and intolerance to physical exercise, although late onset forms are also reported. We describe a case of a 17-year-old male complaining of cramps and myalgia following brief and intense exercise. The patient reported marked improvement in muscle fatigability few minutes after starting aerobic exercise. When he was a child, he had experienced few episodes of vomiting, nausea, and black colored urine following physical activity. Laboratory testings revealed high creatine kinase serum le…

Prognostic information of glycogen phosphorylase isoenzyme BB in patients with suspected acute coronary syndrome.

2012

Early and adequate risk stratification is essential in patients with suspected acute coronary syndrome (ACS). The aim of the present study was to investigate whether glycogen phosphorylase BB (GPBB) could add prognostic information in the context of contemporary sensitive troponin I determination and B-type natriuretic peptide (BNP). Patients with suspected ACS were consecutively enrolled at 3 German study centers from January 2007 through December 2008. Troponin I, GPBB, and BNP were determined at admission. Follow-up information on the combined end point of death, myocardial infarction, revascularization, and hospitalization owing to a cardiovascular cause was obtained 6 months after enro…