EurekaMag.com logo
+ Translate

Regulation of glycogen metabolism and glycogen phosphorylase in physarum polycephalum


, : Regulation of glycogen metabolism and glycogen phosphorylase in physarum polycephalum. Journal of General Microbiology 129(8): 2481-2488

Glycogen and glycogen phosphorylase content of microplasmodia from P. polycephalum were studied during carbohydrate-limited growth and spherulation, induced by starvation. The results indicate that glycogen metabolism in this organism responds most strongly to the availability of external glucose. Glycogen phosphorylase is a constitutive enzyme, present with the same specific molecular activity at all phases of growth and during transition to spherules, supporting the observation that the enzyme cannot be regulated covalently by phosphorylation-dephosphorylation. The enzyme is regulated only by metabolites, in a rather inefficient way: even during net synthesis of glycogen its degradation is not entirely stopped, resulting in a futile cycle. Its activity is merely slowed down to .apprx. 30% of its rate during glycogen breakdown after consumption of glucose. At this time, part of the glycogen, broken down, is apparently used for the synthesis of slime.

(PDF same-day service: $19.90)

Accession: 006288162

DOI: 10.1099/00221287-129-8-2481

Submit PDF Full Text: Here


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Franch, J.; Aslesen, R.; Jensen, J., 1999: Regulation of glycogen synthesis in rat skeletal muscle after glycogen-depleting contractile activity: effects of adrenaline on glycogen synthesis and activation of glycogen synthase and glycogen phosphorylase. We investigated the effects of insulin and adrenaline on the rate of glycogen synthesis in skeletal muscles after electrical stimulation in vitro. The contractile activity decreased the glycogen concentration by 62%. After contractile activity, th...

Lerín, C.; Montell, Eàlia.; Nolasco, T.; García-Rocha, M.; Guinovart, J.J.; Gómez-Foix, A.M., 2003: Regulation of glycogen metabolism in cultured human muscles by the glycogen phosphorylase inhibitor CP-91149. Pharmacological inhibition of liver GP (glycogen phosphorylase), which is currently being studied as a treatment for Type II (noninsulin -dependent) diabetes, may affect muscle glycogen metabolism. In the present study, we analysed the effects of...

Ogawa T.; Araki T.; Tanaka A.; Rikitake Y.; Murooka H.; Yamamori S.; Miyauchi H., 1984: Regulation of glycogen metabolism by glycogen synthetase and phosphorylase in fetal rat liver intrauterine growth retardation. Acta Obstetrica et Gynaecologica Japonica (Japanese Edition) 36(11): 2434

Mellgren, R.L.; Coulson, M., 1983: Coordinated feedback regulation of muscle glycogen metabolism: inhibition of purified phosphorylase phosphatase by glycogen. An assay method was devised for accurately measuring the activity of phosphorylase phosphatase in the presence of glycogen. Both oyster glycogen and rabbit liver glycogen inhibited the activity of purified phosphorylase phosphatase catalytic subun...

Piras, M.M.; Bindstein, E.; Piras, R., 1973: Regulation of glycogen metabolism in the adrenal gland. IV. The effect of insulin on glycogen synthetase, phosphorylase, and related metabolites. Archives of Biochemistry and Biophysics 154(1): 263-269

Piras R., 1973: Regulation of glycogen metabolism in the adrenal gland part 4 the effect of insulin on glycogen synthetase phosphorylase and related metabolites. Archives Of Biochemistry & Biophysics: 263-269

Gómez-Foix, A.M.; Coats, W.S.; Baqué, S.; Alam, T.; Gerard, R.D.; Newgard, C.B., 1992: Adenovirus-mediated transfer of the muscle glycogen phosphorylase gene into hepatocytes confers altered regulation of glycogen metabolism. The muscle isozyme of glycogen phosphorylase is potently activated by the allosteric ligand AMP, whereas the liver isozyme is not. In this study we have investigated the metabolic impact of expression of muscle phosphorylase in liver cells. To thi...

Huang, F.L.; Tao, S.H., 1980: Glycogen metabolism in myogenic cells in culture. Presence of inhibitors for dephosphorylation of glycogen synthase and glycogen phosphorylase. Archives of Biochemistry and Biophysics 199(1): 123-132

Díaz-Lobo, M.; Garcia-Amorós, J.; Fita, I.; Velasco, D.; Guinovart, J.J.; Ferrer, J.C., 2015: Correction: Selective photoregulation of the activity of glycogen synthase and glycogen phosphorylase, two key enzymes in glycogen metabolism. Correction for 'Selective photoregulation of the activity of glycogen synthase and glycogen phosphorylase, two key enzymes in glycogen metabolism' by Mireia Díaz-Lobo, et al., Org. Biomol. Chem., 2015, 13, 7282-7288.

Díaz-Lobo, M.; Garcia-Amorós, J.; Fita, I.; Velasco, D.; Guinovart, J.J.; Ferrer, J.C., 2016: Selective photoregulation of the activity of glycogen synthase and glycogen phosphorylase, two key enzymes in glycogen metabolism. Glycogen is a polymer of α-1,4- and α-1,6-linked glucose units that provides a readily available source of energy in living organisms. Glycogen synthase (GS) and glycogen phosphorylase (GP) are the two enzymes that control, respectively, the syn...