Properties of phospho and dephospho forms of muscle phosphofructokinase.

Foe, Lawrence G.; Kemp, Robert G.

doi:10.1016/s0021-9258(20)65150-x

Cited by 74 publications

(7 citation statements)

References 30 publications

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“…The activation is mainly characterized by a diminution in the inhibitory effects of ATP and, at least for the white-adipose-tissue enzyme, by a decrease in the apparent Km for the activator, fructose 2,6-bisphosphate. This is in apparent contrast with the changes that have been reported to be associated with the phosphorylation of the enzyme from liver or skeletal muscle (Riquelme & Kemp, 1980;Furuya & Uyeda, 1980;Foe & Kemp, 1982;Sakakibara & Uyeda, 1983;Kitajima et al, 1983). In these cases, small increases in the inhibitory effect of ATP and an increase in the apparent Ka for fructose 2,6-bisphosphate were found.…”

Section: Discussioncontrasting

confidence: 72%

Adipose-tissue phosphofructokinase. Rapid purification and regulation by phosphorylation in vitro

Sale¹,

Denton²

1985

Biochemical Journal

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A new procedure for the purification of phosphofructokinase using Blue Dextran-Sepharose is described. This allowed an approx. 1000-fold purification of phosphofructokinase from rat white and brown adipose tissue to be achieved in essentially a single step. The purified enzymes from both tissues were found to exhibit hyperbolic kinetics with fructose 6-phosphate, to be inhibited by ATP and citrate, and to be activated by 5'-AMP, phosphate and fructose 2,6-bisphosphate. The enzymes were phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase, and phosphorylation was found to be associated with increases in activity when the enzymes were assayed under appropriate sub-optimal conditions. In particular, the phosphorylated enzymes exhibited less inhibition by ATP and the white-adipose-tissue enzyme was more sensitive to activation by fructose 2,6-bisphosphate. It is suggested that an increase in the cytoplasmic concentration of cyclic AMP in tissues other than liver may result in an increase in glycolysis through the phosphorylation of phosphofructokinase by cyclic AMP-dependent protein kinase.

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Section: Discussioncontrasting

confidence: 72%

Adipose-tissue phosphofructokinase. Rapid purification and regulation by phosphorylation in vitro

Sale¹,

Denton²

1985

Biochemical Journal

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“…The results in Figure 6 show that calmodulin and troponin C enhance the rate and extent of phosphorylation of the C-terminal site about equally, with the incorporation of ~0.84 mol of phosphate/mol of Ser774 after 2 h of reaction. In contrast, the extent of the phosphorylation of Ser376 ranges from 0.02 mol/mol in the control to 0.16 mol/mol when calmodulin is present, and up to 0.59 mol/mol for samples containing troponin C. In the absence of calmodulin or troponin C, the C-terminal site incorporates only 0.4 equiv of 32P-a fractional stoichiometry that agrees with prevailing reports (Foe & Kemp, 1982;Sale & Denton, 1985).…”

Section: Interaction Of Phosphofructokinase With Troponin C Andsupporting

confidence: 88%

“…However, Foe and Kemp (1982) subsequently determined a maximum incorporation of only 0.4-0.5 mol of phosphate/mol of protomer for the latter case. Similar low stoichiometries have been presented for purified phosphofructokinase from rabbit brain (Foe & Kemp, 1984), rabbit skeletal muscle (Sale & Denton, 1985), and rat liver (Domenech et al, 1988;Mieskes et al, 1987). The major known phosphorylation site of rabbit muscle phosphofructokinase proved to be a serine residue located at the sixth position from the C-terminus of the enzyme (Kemp et al, 1981).…”

supporting

confidence: 69%

“…However, the phosphate content in either case was far below the ideal minimum of 1 mol of phosphate/mol of protomer. Foe and Kemp (1982) later found no difference in either the sedimentation properties, determined under a variety of conditions, or the stabilities of phosphorylated and dephosphorylated enzyme preparations. Yet Kitajima et al (1983) subsequently demonstrated that phosphorylation affects the pH-dependent cold inactivation of the enzyme.…”

mentioning

confidence: 91%

“…The physiological significance of the phosphorylation of phosphofructokinase has been a major point of investigation ever since the discovery of covalently bound phosphate in the purified enzyme. Foe and Kemp (1982) and Kitajima et al (1983) reported that the phosphoenzyme is more sensitive to ATP inhibition than is the dephosphorylated enzyme. However, the differences in catalytic activity are small [see also Soling and Brand (1981), Clark and Patten (1984), and Sakakibara and ].…”

mentioning

confidence: 99%

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Protein-induced inactivation and phosphorylation of rabbit muscle phosphofructokinase

1991

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Several previously untested proteins promote the reversible inactivation of rabbit skeletal muscle phosphofructokinase. Grouped in decreasing order of effectiveness, they include the following: skeletal muscle troponin C greater than troponin, the two smooth muscle myosin light chains, alpha-actinin, and S-100 much greater than parvalbumin and soybean trypsin inhibitor. The efficiency of troponin C in this process may even exceed that previously reported for calmodulin. Sequences near calcium binding site III are apparently involved in the troponin C-phosphofructokinase interaction. Troponin C and calmodulin exert calcium-dependent effects on the physical and chemical properties of muscle phosphofructokinase. When calcium is present, comigration with either protein allows the enzyme to enter the stacking gel during urea-polyacrylamide gel electrophoresis. Both enhance the phosphorylation of phosphofructokinase catalyzed by the cAMP-dependent protein kinase, with phosphate incorporations approaching 2 mol of P/mol of protomer. Reaction occurs at Ser774 and at Ser376--a novel site whose phosphorylation is highly sensitive to troponin C and less so to calmodulin. Maximum phosphorylation has slight effect on the catalytic activity of the enzyme under standard assay conditions. The troponin C induced or calmodulin-induced phosphorylation of phosphofructokinase requires calcium and is strongly inhibited by either fructose 2,6-bisphosphate or fructose 1,6-bisphosphate. Inactivation occurs in the presence or absence of calcium, with generally higher concentrations of effectors required for protection in the latter case. Liver and yeast phosphofructokinases shows little activity loss in the presence of either calmodulin or troponin C. We have developed and tested a general mathematical model for the protein-induced inactivation of phosphofructokinase which may find application to other systems.

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Fructose 2,6‐Bisphosphate

Schaftingen

1987

Advances in Enzymology - And Related Areas of Molecular Biology

171

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Properties of phospho and dephospho forms of muscle phosphofructokinase.

Cited by 74 publications

References 30 publications

Adipose-tissue phosphofructokinase. Rapid purification and regulation by phosphorylation in vitro

Adipose-tissue phosphofructokinase. Rapid purification and regulation by phosphorylation in vitro

Protein-induced inactivation and phosphorylation of rabbit muscle phosphofructokinase

Fructose 2,6‐Bisphosphate

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