Effect of ACTH &lt;I&gt;in vivo&lt;/I&gt; on the Phospholipid Exchange between Adrenal Microsomes and Mitochondria &lt;I&gt;in vitro&lt;/I&gt;

Ichii, Shogo

doi:10.1507/endocrj1954.19.203

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…The ammonium sulphate fraction was then desalted by passage through a Sephadex G25 column (30 x 2 cm) equilibrated with 50 mM sodium glycerophosphate buffer pH 6.5, 1 mM MgC12, 4 mM sodium fluoride and 2 mM theophylline and the protein fractions were pooled. This procedure removed endogenous nucleotides and gave the optimal conditions for protein kinase activity [31].…”

Section: Preincubation Of the Ammonium Sulphate Fraction With [~-~' Pmentioning

confidence: 99%

Purification and Control of Bovine Adrenal Cortical Cholesterol Ester Hydrolase and Evidence for the Activation of the Enzyme by a Phosphorylation

Beckett

Boyd

1977

European Journal of Biochemistry

112

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A procedure for the purification of cholesterol ester hydrolase from bovine adrenal cortical 105 000 x g supernatant is described. Preincubation of a crude enzyme extract with [Y-~~PIATP followed by purification resulted in the isolation of a phosphorylated preparation of cholesterol ester hydrolase. The phosphorylated cholesterol ester hydrolase appeared to be composed of 4 subunits, each having a molecular weight of 41 000 280, only one of which may be phosphorylated. Preincubation of the crude enzyme preparation with [w3'P]ATP followed by purification did not produce a phosphorylated preparation of cholesterol ester hydrolase.Cyclic-AMP-dependent protein kinase, cyclic AMP, ATP and magnesium ions were required for activation of purified cholesterol ester hydrolase in vitro and the time course of activation closely paralleled the time course of phosphorylation of the enzyme. The addition of ATP, cyclic AMP and magnesium ions to the bovine adrenal cortical 105000 x g supernatant produced a 2.5-fold stimulatiun in cholesterol ester hydrolase activity. This stimulation was abolished if protein kinase inhibitor was added prior to the addition of ATP, cyclic AMP and magnesium ions.The addition of magnesium ions or calcium ions to a crude preparation of cholesterol ester hydrolase was found to inhibit activity; however the same additions made to a purified preparation of cholesterol ester hydrolase were not inhibitory. The decrease in cholesterol ester hydrolase activity on incubation with magnesium ions was accompanied by a loss of 32P radioactivity from the protein.Preincubation of a crude preparation of cholesterol ester hydrolase with alkaline phosphatase resulted in a deactivation of cholesterol ester hydrolase.It is suggested that bovine adrenal cortex cholesterol ester hydrolase is activated by a phosphorylation catalysed by a cyclic-AMP-dependent protein kinase. Deactivation of cholesterol ester hydrolase is accomplished by dephosphorylation catalysed by a phosphoprotein phosphatase, dependent on magnesium or calcium ions.Cholesterol ester hydrolase, the enzyme which effects the hydrolysis of cholesterol esters, is found in the 105000 x g supernatant fraction of both the rat and bovine adrenal cortex. A significant decrease in the adrenal cholesterol ester content, concomitant with an increased activity of cholesterol ester hydrolase, is produced when the rat is subjected to conditions which elevate plasma adrenocorticotropin concentrations [l-51. Stimulation of both rat and bovine Abbreviations and Trivial Names. Cyclic AMP, adenosine 3'-5'-monophospl~ate; dodecylsulphate, Sodium dodecylsulphate ; cholesterol, 5-cholesten-38-01; pregnenolone, 3P-Hydroxy-5-pregnen-20-one.Enzymes. Cholesterol ester hydrolase or sterol ester hydrolase (EC 3.1

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Section: Preincubation Of the Ammonium Sulphate Fraction With [~-~' Pmentioning

confidence: 99%

Purification and Control of Bovine Adrenal Cortical Cholesterol Ester Hydrolase and Evidence for the Activation of the Enzyme by a Phosphorylation

Beckett

Boyd

1977

European Journal of Biochemistry

112

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“…The cyclic AMP assay of Brown et al (1971) has been reported to be useful also when bound and free radioactivity is separated with membrane filters (Tsang et-al., 1972;Ichii, 1972;Albano et al, 1974) or by (NH4)2SO4 precipitation (Rabinowitz & Katz, 1973). The standard curve for this assay by (NHF)2SO4 precipitation was plotted in the conventional manner ( Fig.…”

Section: Characteristics Of Cyclic (3h]amp Binding By Adrenal-cortex mentioning

confidence: 99%

“…The cyclic AMP-dependent protein kinases have subunits whose specificity and high affinity for cyclic AMP make these enzymes useful as binding reagents in competitive-binding assays for this nucleotide. The binding reagent is minimally purified tissue extracts (Brown et al, 1971;Ichii, 1972;Tsang et al, 1972;Rabinowitz & Katz, 1973;Cooper et al, 1972), the isoenzyme form of protein kinase eluted from DEAE-cellulose at low ionic strength (Brostrom & Kon, 1974;Tovey et al, 1974) or the protein kinase isoenzyme eluted at higher ionic strength (Gilman, 1970;Walton & Garren, 1970;Sanborn etal., 1973). Bound and free isotope is most often separated by membrane filtration (Gilman, 1970;Walton & Garren, 1970;Ichii, 1972;Sanborn et al, 1973;Gilman & Murad, 1974;Gill & Walton, 1974) or dextran-coated charcoal (Brown et al, 1971;Tovey et al, 1974).…”

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confidence: 99%

Factors affecting the binding of [3H]adenosine 3′:5′-cyclic monophosphate to protein kinase from bovine adrenal cortex

Døskeland¹,

Ueland²,

Haga³

1977

Biochemical Journal

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Inorganic salts, several proteins and traces of protein precipitants were tested to find out by what mechanisms they modulate the binding of cyclic [3H]AMP to protein kinase (ATP-protein phosphotransferase; EC 2.7.1.37). The separation of free and bound cyclic AMP by (NH4)2SO4 precipitation was unaffected by the above agents and was more reliable than the Millipore filtration technique. Several binding sites for cyclic AMP were revealed in adrenal-cortex extract. When this extract was used as binding reagent in an assay for cyclic AMP, the standard curve was distorted in the presence of KCl because the salt affected the different binding sites to a varying extent. At high ionic strenth the protein kinase isoenzyme I dissociated and showed an extraordinarily high affinity for cyclic AMP. Trichloroacetate and perchlorate at very low concentrations were able to dissociate the protein kinase and modulate its binding characteristics as well. A progressive decrease in the cyclic AMP-binding capacity occurred on prolonged incubations. The binding protein was protected against inactivation by 2-mercaptoethanol, EDTA and several proteins. It was more resistant to denaturation when complexed to cyclic AMP. The enhancement of cyclic AMP binding by bovine serum albumin was investigated in some detail and appeared to be a pure stabilizing effect. It is proposed that the competitive-binding assays for cyclic AMP based on protein kinase be conducted at high ionic strength and in the presence of stabilizers (protein, EDTA, 2-mercaptoethanol). The interference from agents that may dissociate the protein kinase or influence its stability will thus be decreased.

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Effects of ACTH and diabetes on phospholipid metabolism in adrenal mitochondria

1977

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Incorporation of 32P into adrenal mitochondrial phospholipids (PL) incrased in ACTH-treated rats, but it decreased in diabetics, inspite of the fact that these animals showed adrenal overacity. Since diabetics did not show increased 11 beta-hydroxylation. as opposed to ACTH-treated rats, it is suggested that the stimulation of this enzyme activity by exogenous ACTH is related to an increased turnover of PL at the mitochondrial membrane. The process is impaired in diabetics and prevents the stimulation of 11 beta-hydroxylation.

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Effect of ACTH <I>in vivo</I> on the Phospholipid Exchange between Adrenal Microsomes and Mitochondria <I>in vitro</I>

Cited by 3 publications

References 4 publications

Purification and Control of Bovine Adrenal Cortical Cholesterol Ester Hydrolase and Evidence for the Activation of the Enzyme by a Phosphorylation

Purification and Control of Bovine Adrenal Cortical Cholesterol Ester Hydrolase and Evidence for the Activation of the Enzyme by a Phosphorylation

Factors affecting the binding of [3H]adenosine 3′:5′-cyclic monophosphate to protein kinase from bovine adrenal cortex

Effects of ACTH and diabetes on phospholipid metabolism in adrenal mitochondria

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