Hormone-stimulated phosphorylation of liver phosphofructokinase in vivo

T. Kagimoto, K. Uyeda

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

The effect of glucagon on the phosphorylation, and the enzymic activity of phosphofructokinase in rat liver in vivo was investigated. Glucagon stimulated the phosphorylation of liver phosphofructokinase approximately 3- to 5-fold and increased cAMP levels 5-fold and blood glucose levels 2-fold over the values obtained for control animals. The specific radioactivity of ATP isolated from liver was the same in both control and hormone-treated animals. During the purification of the 32P-labeled enzyme from both animals, no difference was observed in the total or specific enzyme activities of the enzymes from the various fractions. Thus, phosphofructokinase appears to be phosphorylated in vivo by a cyclic AMP-dependent protein kinase Although phosphorylation does not affect the maximum catalytic activity of the enzyme, it does render the enzyme significantly more sensitive to ATP inhibition. Thus, at a given concentration of ATP, the phosphorylated phosphofructokinase exhibits considerably lower activity than the unphosphorylated enzyme. The possible relationship between our observations and glucagon-mediated control of glycolysis is discussed.

Original languageEnglish (US)
Pages (from-to)5584-5587
Number of pages4
JournalJournal of Biological Chemistry
Volume254
Issue number13
StatePublished - 1979

Fingerprint

Phosphofructokinases
Phosphorylation
Liver
Hormones
Glucagon
Enzymes
Animals
Adenosine Triphosphate
Radioactivity
Enzyme activity
Cyclic AMP-Dependent Protein Kinases
Purification
Glycolysis
Blood Glucose
Rats
Catalyst activity

ASJC Scopus subject areas

  • Biochemistry

Cite this

Hormone-stimulated phosphorylation of liver phosphofructokinase in vivo. / Kagimoto, T.; Uyeda, K.

In: Journal of Biological Chemistry, Vol. 254, No. 13, 1979, p. 5584-5587.

Research output: Contribution to journalArticle

@article{304bc489df3a4760ab0a89fafdb887cf,
title = "Hormone-stimulated phosphorylation of liver phosphofructokinase in vivo",
abstract = "The effect of glucagon on the phosphorylation, and the enzymic activity of phosphofructokinase in rat liver in vivo was investigated. Glucagon stimulated the phosphorylation of liver phosphofructokinase approximately 3- to 5-fold and increased cAMP levels 5-fold and blood glucose levels 2-fold over the values obtained for control animals. The specific radioactivity of ATP isolated from liver was the same in both control and hormone-treated animals. During the purification of the 32P-labeled enzyme from both animals, no difference was observed in the total or specific enzyme activities of the enzymes from the various fractions. Thus, phosphofructokinase appears to be phosphorylated in vivo by a cyclic AMP-dependent protein kinase Although phosphorylation does not affect the maximum catalytic activity of the enzyme, it does render the enzyme significantly more sensitive to ATP inhibition. Thus, at a given concentration of ATP, the phosphorylated phosphofructokinase exhibits considerably lower activity than the unphosphorylated enzyme. The possible relationship between our observations and glucagon-mediated control of glycolysis is discussed.",
author = "T. Kagimoto and K. Uyeda",
year = "1979",
language = "English (US)",
volume = "254",
pages = "5584--5587",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "13",

}

TY - JOUR

T1 - Hormone-stimulated phosphorylation of liver phosphofructokinase in vivo

AU - Kagimoto, T.

AU - Uyeda, K.

PY - 1979

Y1 - 1979

N2 - The effect of glucagon on the phosphorylation, and the enzymic activity of phosphofructokinase in rat liver in vivo was investigated. Glucagon stimulated the phosphorylation of liver phosphofructokinase approximately 3- to 5-fold and increased cAMP levels 5-fold and blood glucose levels 2-fold over the values obtained for control animals. The specific radioactivity of ATP isolated from liver was the same in both control and hormone-treated animals. During the purification of the 32P-labeled enzyme from both animals, no difference was observed in the total or specific enzyme activities of the enzymes from the various fractions. Thus, phosphofructokinase appears to be phosphorylated in vivo by a cyclic AMP-dependent protein kinase Although phosphorylation does not affect the maximum catalytic activity of the enzyme, it does render the enzyme significantly more sensitive to ATP inhibition. Thus, at a given concentration of ATP, the phosphorylated phosphofructokinase exhibits considerably lower activity than the unphosphorylated enzyme. The possible relationship between our observations and glucagon-mediated control of glycolysis is discussed.

AB - The effect of glucagon on the phosphorylation, and the enzymic activity of phosphofructokinase in rat liver in vivo was investigated. Glucagon stimulated the phosphorylation of liver phosphofructokinase approximately 3- to 5-fold and increased cAMP levels 5-fold and blood glucose levels 2-fold over the values obtained for control animals. The specific radioactivity of ATP isolated from liver was the same in both control and hormone-treated animals. During the purification of the 32P-labeled enzyme from both animals, no difference was observed in the total or specific enzyme activities of the enzymes from the various fractions. Thus, phosphofructokinase appears to be phosphorylated in vivo by a cyclic AMP-dependent protein kinase Although phosphorylation does not affect the maximum catalytic activity of the enzyme, it does render the enzyme significantly more sensitive to ATP inhibition. Thus, at a given concentration of ATP, the phosphorylated phosphofructokinase exhibits considerably lower activity than the unphosphorylated enzyme. The possible relationship between our observations and glucagon-mediated control of glycolysis is discussed.

UR - http://www.scopus.com/inward/record.url?scp=0018648819&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0018648819&partnerID=8YFLogxK

M3 - Article

VL - 254

SP - 5584

EP - 5587

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 13

ER -