Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.4.1.2 (acetyl-CoA carboxylase)
 2,876 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protein kinase, termed microtubule-associated protein (MAP) kinase, which phosphorylates microtubule-associated protein 2 (MAP-2) in vitro and is stimulated 1.5-3-fold in extracts from insulin-treated 3T3-L1 cells has been identified (Ray, L.B., and Sturgill, T.W. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 1502-1506). Here, we describe chromatographic properties of MAP kinase and provide biochemical characterization of the partially purified enzyme. Isolation of the enzyme is facilitated by its unusually high affinity for hydrophobic interaction chromatography matrices. The molecular weight of the partially purified enzyme was determined to be 35,000 by gel filtration chromatography and 37,000 by glycerol gradient centrifugation. MAP kinase activity of chromatographic fractions correlated precisely with the presence of a 40-kDa phosphoprotein detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. MAP kinase has a Km of 7 microM for ATP and does not utilize GTP. Acetyl-CoA carboxylase, ATP citrate-lyase, casein, histones, phosvitin, protamine, and ribosomal protein S6 were all poor substrates relative to MAP-2. The enzyme is inhibited by fluoride and beta-glycerol phosphate but not by heparin. These properties of MAP kinase distinguish it from protein kinases previously described in the literature.
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PMID:Characterization of insulin-stimulated microtubule-associated protein kinase. Rapid isolation and stabilization of a novel serine/threonine kinase from 3T3-L1 cells. 284 41

The activity of acetyl-CoA carboxylase (ACC), the rate-limiting enzyme of fatty acid biosynthesis, can be regulated by both adenine and guanine nucleotides in vitro. We have employed two inhibitors of IMP dehydrogenase, ribavarin and tiazofurin, to investigate a possible role for intracellular nucleotides in ACC regulation in rat adipocytes. Ribavarin, but not tiazofurin, leads to a profound time-dependent inhibition of ACC activity that is associated with a decrease in both intracellular ATP and GTP. This inactivating effect is largely reversed with guanosine, accompanied by increases in both ATP and GTP levels. Epinephrine-mediated inactivation of ACC in intact cells is not altered by ribavarin incubation. However, in these experiments, insulin-mediated activation is observed only after ribavarin-induced inhibition of the enzyme. These data suggest that nucleotides may modulate ACC activity and influence is regulation by insulin in intact cells. The possible mechanisms underlying the insulin activation of ACC and the role of intracellular nucleotides in insulin action are discussed.
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PMID:Modulation of acetyl-CoA carboxylase by inhibitors of IMP dehydrogenase: implications for insulin regulation. 288 May 60

A multifunctional protein kinase, purified from rat liver as ATP-citrate lyase kinase, has been identified as a glycogen synthase kinase. This kinase catalyzed incorporation of up to 1.5 mol of 32PO4/mol of synthase subunit associated with a decrease in the glycogen synthase activity ratio from 0.85 to a value of 0.15. Approximately 65-70% of the 32PO4 was incorporated into site 3 and 30-35% into site 2 as determined by reverse phase high performance liquid chromatography. Release of 32PO4 from the phosphopeptides during automated Edman degradation confirmed the site 3 and 2 assignment. Thermal stability studies established that the phosphorylations of sites 3 and 2 were catalyzed by the same kinase. This multifunctional kinase was distinguished from glycogen synthase kinase-3 on the basis of nucleotide (ATP versus GTP) and protein substrate (glycogen synthase, ATP-citrate lyase, and acetyl-CoA carboxylase) specificities. Since the phosphate contents in glycogen synthase of sites 3 and 2 are altered in diabetes and by insulin administration, the possible involvement of the multifunctional kinase was explored. Glycogen synthase purified from diabetic rabbits was phosphorylated in vitro by this multifunctional kinase at only 10% of the rate compared to synthase purified from control rabbits. Treatment of the diabetics with insulin restored the synthase to a form that was readily phosphorylated in vitro.
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PMID:Phosphorylation of sites 3 and 2 in rabbit skeletal muscle glycogen synthase by a multifunctional protein kinase (ATP-citrate lyase kinase). 393 Apr 92

Two cAMP-independent acetyl-CoA carboxylase (ACC) protein kinases have been partially purified from rat liver cytosol and microsomal extracts. The first kinase, present in greatest activity in microsomal extracts, appears to be identical to casein kinase I by characteristic molecular size on gel filtration (Mr 40,000) and sodium dodecyl sulfate-gel electrophoresis (Mr 34,000), autophosphorylation of this single subunit, inability to efficiently utilize GTP, and resistance to inhibition by heparin and 2,3-diphosphoglycerate. The second kinase, predominant in cytosol, appears to be identical to casein kinase II by characteristic molecular size on gel filtration (Mr 150,000), an autophosphorylated subunit of Mr 25,000, a Km for GTP nearly equal to that of ATP, inhibition by heparin and 2,3 DPG, and relative substrate specificity. Despite the incorporation of up to 2 mol 32P/mol carboxylase subunit (kinase I) and 0.6 mol/subunit (kinase II), phosphorylation by either kinase causes no change in carboxylase activity. The site(s) phosphorylated by each kinase and by the cAMP-dependent protein kinase on carboxylase appear to be clustered on a Mr 16,000 cyanogen bromide peptide that is readily released on incubation with trypsin. The potential roles of these kinases in the regulation of ACC remain to be clarified.
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PMID:Phosphorylation of acetyl-coenzyme A carboxylase by casein kinase I and casein kinase II. 614 63

Acetyl-CoA carboxylase was purified 300-fold from rat liver, in the absence of added citrate, by precipitation from an 18,000g supernatant in the presence of Triton X-100 at 105,000g and 20 degrees C, followed by chromatography on phosphocellulose. Acetyl-CoA carboxylase activity in this preparation was activated by preincubation with GTP (0.1-2.0 mM) and with citrate (20 mM). Colchicine (10(-6)-10(-3) M) inhibited enzyme activity and counteracted the effects of GTP and citrate. Sucrose density gradient centrifugation demonstrated that GTP and citrate preincubation promoted the formation of the polymeric, active enzyme, while colchicine engendered disassembly. Preincubation of the purified acetyl-CoA carboxylase at 4 degrees C caused inactivation and disassembly, which was countered by preincubation at 37 degrees C in the presence of GTP or citrate. These results suggest that GTP, like citrate, activates acetyl-CoA carboxylase by enhancing the conversion of the protomeric form of the enzyme to its more active, polymeric state.
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PMID:Guanosine triphosphate and colchicine affect the activity and the polymeric state of acetyl-CoA carboxylase. 614 16

Nucleoside diphosphate kinase (NDPK, NM23/awd) belongs to a multifunctional family of highly conserved proteins (approximately 16-20 kDa) containing two well-characterized isoforms (NM23-H1 and -H2; also known as NDPK A and B). NDPK catalyses the conversion of nucleoside diphosphates into nucleoside triphosphates, regulates a diverse array of cellular events and can act as a protein histidine kinase. AMPK (AMP-activated protein kinase) is a heterotrimeric protein complex that responds to cellular energy status by switching off ATP-consuming pathways and switching on ATP-generating pathways when ATP is limiting. AMPK was first discovered as an activity that inhibited preparations of ACC1 (acetyl-CoA carboxylase), a regulator of cellular fatty acid synthesis. We report that NM23-H1/NDPK A and AMPK alpha1 are associated in cytosol from two different tissue sources: rat liver and a human lung cell line (Calu-3). Co-immunoprecipitation and binding assay data from both cell types show that the H1/A (but not H2/B) isoform of NDPK is associated with AMPK complexes containing the alpha1 (but not alpha2) catalytic subunit. Manipulation of NM23-H1/NDPK A nucleotide transphosphorylation activity to generate ATP (but not GTP) enhances the activity of AMPK towards its specific peptide substrate in vitro and also regulates the phosphorylation of ACC1, an in vivo target for AMPK. Thus novel NM23-H1/NDPK A-dependent regulation of AMPK alpha1-mediated phosphorylation is present in mammalian cells.
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PMID:A novel physical and functional association between nucleoside diphosphate kinase A and AMP-activated protein kinase alpha1 in liver and lung. 1916 May 68