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)

The biotin carboxyl carrier protein (BCCP) component of Escherichia coli acetyl coenzyme A carboxylase and three peptides derived from BCCP by proteolytic digestion have been examined by circular dichroism spectroscopy. BCCP, which has a peptide molecular weight of 22,500, has a spectrum typical of globular proteins with negative extrema at 222 nm and 208 nm. The two smallest peptides, BCCP(SC) and BCCP(9,100), with molecular weights of 8,900 and 9,100, respectively, exhibit unusual positive CD bands centered at 237 nm and 220 nm. BCCP(10,400), with a molecular weight of 10,400, has a CD spectrum intermediate between BCCP and that of the smallest peptides. Since d-biotin exhibits a positive CD band at 233 nm, it was suspected that the biotin prosthetic group might be the chromophore responsible for the 237 nm CD band seen in BCCP(SC) and BCCP(9,100). Enzymatic carboxylation of BCCP(SC) to form CO2-BCCP(SC) caused the CD spectrum to change with a shift of the 237 nm band to 232 nm. The positive CD band at 220 nm was unaffected by carboxylation of the biotin prosthetic group. These date suggest that the 237 nm signal may be due either to the biotin which acts as a chromophore directly or to a chromophore that is perturbed by the carboxylation of biotin. A spectropolarimetric titration was carried out to investigate the possible contribution of the single tyrosine residue of BCCP(SC) to the CD spectrum of this peptide. At pH values over 9 the CD spetrum changed with the disappearance of the 237 nm band, suggesting that tyrosine might contribute to this CD band. Denaturation of BCCP(SC) or BCCP(9,100) with 8 M urea of 6 M guanidine HCl abolished the positive CD bands and resulted in spectra typical of a random coil, whereas treatment of BCCP(SC) with 1% sodium dodecyl sulfate abolished the positive bands and left a spectrum exhibiting a shoulder at 222 nm and a negative band at 205 nm, suggestive of a high degree of ordered structure. It is concluded that the CD band at 237 nm in BCCP(SC) and BCCP(9,100) is prabably due to a noncovalent interaction of biotin with an amino acid residue(s) of the protein. It is suggested that the biotin prosthetic group is partially buried in the surface of the protein, rather than swinging free at the end of the lysine side chain through which it is covalently linked to the protein, to permit this interaction to occur.
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PMID:Acetyl coenzyme A carbosylase. Circular dichroism studies of Escherichia coli biotin carboxyl carrier protein. 0 38

The interaction of stearoyl-(1,N6)-etheno coenzyme A (stearoyl-epsilon-CoA) with acetyl coenzyme A carboxylase was investigated by using fluorescence spectroscopy. The fluorescence emission of stearoyl-epsilon-CoA was partially quenched by acetyl coenzyme A carboxylase. Analysis of the data for dissociation constant (KD) and the stoichiometry of the interaction (n) gave values of 5.06 nM and 1.2, respectively, at pH 7.6 in 50 mM Tris-HCl and 25 degrees C. The KD value is comparable to the inhibition constant (Ki) obtained previously by others for the inhibition of rat liver acetyl coenzyme A carboxylase by long chain fatty acyl-CoAs. Citrate (which is known to polymerize and thus activate carboxylase) caused a partial quenching of the protein fluorescence of carboxylase, presumably due to polymerization of the enzyme. The quenching of the stearoyl-epsilon-CoA fluorescence caused by carboxylase as well as the inhibition of carboxylase activity by stearoyl-epsilon-CoA was reversed by citrate, but only in the presence of 6-O-methylglucose polysaccharide which forms a stable complex with fatty acyl-CoA. This shows that the stearoyl-epsilon-CoA bound to the enzyme is displaced by citrate only in the presence of an acceptor of fatty acyl-CoA. These results support the reciprocal relationship of citrate and fatty acyl-CoA in the regulation of acetyl coenzyme A carboxylase.
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PMID:Interaction of the fluorescent analogue stearoyl-(1,N6)-etheno coenzyme A with chicken liver acetyl coenzyme A carboxylase. 610 64

Acetyl-CoA carboxylase from irradiated cell-suspension cultures of parsley (Petroselinum hortense) has been purified to apparent homogeneity. The procedure included affinity chromatography of the enzyme on avidinmonomer--Sepharose 4B. Molecular weights of about 420000 for the native enzyme and about 220000 for the enzyme subunit were determined respectively by gel filtration or sucrose-density-gradient sedimentation and by electrophoresis in the presence of dodecyl sulfate. The purified enzyme showed an isoelectric point of 5. The enzyme carboxylated the straight-chain acyl-CoA esters of acetate, propionate, and butyrate at decreasing rates in this order. The catalytic efficiency of the carboxylase was highest when ATP existed largely as MgATP2- complex. At the optimum pH of 8 the apparent Km values for the substrates were: acetyl-CoA, 0.15 mmol/1; bicarbonate, 1 mmol/1; MgATP2-, 0.07 mmol/1. The carboxylase was inhibited by greater than 50 mmol/l NaCl, KCl, or Tris/HCl buffer. The putative allosteric activator, citrate, stimulated the enzyme only slightly at concentrations below 2 mmol/l, but strongly inhibited the carboxylase at higher concentrations. The results of these studies demonstrate that several properties of the light-inducible acetyl-CoA carboxylase of parsley cells, an enzyme of the flavonoid pathway, are remarkably similar to those of acetyl-CoA carboxylases from a variety of other organisms.
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PMID:Improved purification and further characterization of acetyl-CoA carboxylase from cultured cells of parsley (Petroselinum hortense). 613 48