Activities of Glycogen Synthetase and UDPG-pyrophosphorylase in Muscle of a Patient with a New Type of Muscle Glycogenosis caused by Phosphofructokinase Deficiency

Okuno, Giichi; Hizukuri, Susumu; Nishikawa, Mitsuo

doi:10.1038/2121490a0

Cited by 14 publications

(3 citation statements)

References 8 publications

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“…The once all-important metabolite regulation may, in the new environment, have been entrusted with the sole task of giving significance to the interconversion mechanism, as discussed above. It is, however, conceivable that in certain situations the metabolite level directly affects the enzymatic activity as, for instance, in the case reported by Okuno et al (1966). They found that a genetically determined lack of phosphofructokinase was accompanied by a large increase in the glucose-6-P concentration and by an accumulation of glycogen.…”

Section: Discussionmentioning

confidence: 95%

Regulation of muscle glycogen synthetase by metabolites. Differential effects on the I and D forms

Piras¹,

Rothman²,

Cabib³

1968

Biochemistry

153

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Both the glucose 6-phosphate independent (I) and the glucose 6-phosphate dependent (D) forms of rat muscle glycogen synthetase are inhibited by adenosine triphosphate (ATP), adenosine diphosphate (ADP), and P¡. The inhibition is, kinetically, of the competitive type with respect to uridine diphosphate glucose (UDP-glucose). Glucose 6-phosphate reverses this inhibition, without affecting, at pH 6.6, the Km for UDP-glucose. UDP, one of the reaction products, is a strong inhibitor and its effect is not reversed by glucose 6-phosphate. Photooxidation of the I form in the presence of methylene blue causes a preferential loss of the inhibition by ATP, as compared to that by UDP. The sum of this evidence suggests that UDP-

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Section: Discussionmentioning

confidence: 95%

Regulation of muscle glycogen synthetase by metabolites. Differential effects on the I and D forms

Piras¹,

Rothman²,

Cabib³

1968

Biochemistry

153

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“…The increase of glycogen was initially attributed not only to the block of glycolysis but also to increased activity of glycogen synthetase (41). Subsequent studies showed that the increased activity of glycogen synthetase was secondary to the increased content of Glu-6-P (see below), an activator of the enzyme (29,42).…”

Section: Discussionmentioning

confidence: 99%

Heterogeneity of the molecular lesions in inherited phosphofructokinase deficiency.

et al. 1983

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A B S T R A C T Human phosphofructokinase (PFK; EC 2.7.1.11) exists in tetrameric isozymic forms. Muscle and liver contain the homotetramers M4 and L4, whereas erythrocytes contain five isozymes composed of M (muscle) and L (liver) subunits, i.e., M4, M3L, M2L2, ML3, and L4. Inherited defects of erythrocyte PFK are usually partial and are described in association with heterogeneous clinical syndromes. To define the molecular basis and pathogenesis of this enzymopathy, we investigated four unrelated individuals manifesting myopathy and hemolysis (glycogenosis type VII), isolated hemolysis, or no symptoms at all.The three symptomatic patients showed high-normal hemoglobin levels, despite hemolysis and early-onset hyperuricemia. They showed total lack of muscle-type PFK and suffered from exertional myopathy of varying severity. In the erythrocytes, a metabolic crossover was evident at the PFK step: the levels of hexose monophosphates were elevated and those of 2,3-diphosphoglycerate (2,3-DPG) were depressed, causing strikingly increased hemoglobin-oxygen affinity. In all cases,

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“…One was recently found to result from a deficiency in phospho-fructokinase [15,20]. In a different family exhibiting the clinical symptoms of Mac Ardle's disease, there was no elevation of lactic acid levels in muscle homogenates unless fructose-6-phosphate or fructose-l-6-diphosphate were added.…”

Section: During Human Muscular Diseasesmentioning

confidence: 99%

Biochemistry of Striated Muscle During Human Muscular Diseases

Schapira¹,

Dreyfus²,

Schapira³

1970

Enzymol Biol Clin

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Activities of Glycogen Synthetase and UDPG-pyrophosphorylase in Muscle of a Patient with a New Type of Muscle Glycogenosis caused by Phosphofructokinase Deficiency

Cited by 14 publications

References 8 publications

Regulation of muscle glycogen synthetase by metabolites. Differential effects on the I and D forms

Regulation of muscle glycogen synthetase by metabolites. Differential effects on the I and D forms

Heterogeneity of the molecular lesions in inherited phosphofructokinase deficiency.

Biochemistry of Striated Muscle During Human Muscular Diseases

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