共查询到20条相似文献,搜索用时 125 毫秒
1.
《Neurochemistry international》1987,11(3):265-271
Tryptophan hydroxylation in cockroach (Periplaneta americana) nervous tissue was measured and compared to the hydroxylation of tryptophan in rat brain. Tryptophan hydroxylation in both tissues requires a pterine cofactor, and is inhibited by p-chlorophenylalanine. The molecular weight of the protein responsible for hydroxylation of tryptophan in cockroach nervous tissue obtained from gel filtration was estimated to be 54,000.The pH optima and enzyme kinetics differed greatly between the two hydroxylases. Hydroxylation of tryptophan by the enzyme obtained from cockroach tissues incubated with dimethyltetrahydropterine had a pH optimum of about 5.8–5.9 and a Km in crude enzyme preparations of 2.6 × 10−6 M and is activity was substrate inhibited above 10−4 M tryptophan. Hydroxylation of tryptophan by the enzyme obtained from rat brain incubated with dimethyltetrahydropterine had a pH optimum of about 6.5–7.0, a Km of about 6.7 × 10−4 M and exhibited no substrate inhibition at tryptophan concentrations up to 2 × 10−3 M.When incubated with biopterin, the presumed natural cofactor, the hydroxylase from cockroach tissues had a Km of about 6.8 × 10−5 M and no substrate inhibition occurred at tryptophan concentrations up to 2 × 10−3 M. Under the same conditions rat hydroxylase had a Km of 1.1 × 10−5M and substrate inhibition occurred above 10−4 M tryptophan.Unlike the mammalian situation, administration of tryptophan peripherally did not change the 5-hydroxytryptamine concentration in cockroach nervous tissue, but did increase tryptophan levels. The low Vmax values of the cockroach hydroxylase and the inability of administered tryptophan to elevate 5-hydroxytryptamine levels suggest that in the cockroach hydroxylation of tryptophan itself may be the limiting factor in the biosynthesis of 5-hydroxytryptamine. 相似文献
2.
Calmodulin-dependent NAD kinase has been purified more than 70fold from a crude plant (zucchini squash) homogenate by calmodulin-Sepharose affinity chromatography to a specific activity of 80 munits/mg protein. The enzyme could be activated about 8fold by calmodulin. Half-maximal activation was obtained with 6 ng of purified calmodulin from bovine brain. Together with NAD kinase other soluble plant proteins were retained specifically on the column. NaDodSo4 polyacrylamide gel electrophoresis of the proteins which were retained by the calmodulin-Sepharose column revealed at least 7 to 8 bands. Most of the intensively stained bands on the gels obtained from the crude homogenate had disappeared. 相似文献
3.
Yong-Ming Zhang Jeyanthi Rebecca Livingstone Eiji Hirasawa 《Acta Physiologiae Plantarum》2012,34(4):1411-1419
FAD-containing monoamine oxidase (MAO; EC 1.4.3.4) oxidises monoamines to their corresponding aldehydes, H2O2, and NH3. It has been purified to homogeneity in mammals, but to our knowledge, there have been no reports of the enzyme in plants. MAO activity was detected in Avena sativa seedlings during germination using benzylamine as substrate. The enzyme was purified to homogeneity (as assessed by native PAGE) by Sephadex G-25, DEAE Sephacel, hydroxyapatite, Mono Q, and TSK-GEL column chromatographies. The molecular mass estimated by gel filtration using the TSK-GEL column was 220?kDa. SDS-PAGE yielded four distinct protein bands of 78, 58, 55, and 32?kDa molecular masses. The pI value of the enzyme was 6.3. The enzyme showed high substrate specificity for an endogenous amine, phenethylamine, which was oxidised to phenylacetaldehde, but not for ethylamine, propylamine, butylamine, pentylamine, dopamine, serotonin, tryptamine, or tyramine. The K m values for benzylamine and phenethylamine were 2.7?×?10?4 and 7.1?×?10?4?M, respectively. Enzyme activity was not inhibited by pargyline, clorgyline, semicarbazide, or Na-diethyldithiocarbamate. Benzaldehyde, the product of benzylamine oxidation, exhibited strong competitive inhibition of enzyme activity with a Ki of 3???M. FAD was identified by ODS-column chromatography as an enzyme cofactor. The enzyme contained 2?mol of FAD per 220,000?g of enzyme. 相似文献
4.
Ethanolamine kinase was partially purified from the larvae of Culex pipiens fatigans and its properties were studied. The enzyme was separated from choline kinase by acetic acid precipitation at pH 5.0 of a 13,000g supernatant of the larval homogenate. Alkaline phosphatase activity was removed from the enzyme preparation by the acid treatment followed by ammonium sulfate fractionation. The enzyme was localized in the cytosolic fraction and had a requirement for Mg2+ as a cofactor. The Km values for ethanolamine and ATP were 4 × 10?4 and 1.54 × 10?4m, respectively. The affinity of the enzyme for nucleotide triphosphates was in the order, ATP > ITP > GTP while UTP and CTP were poorly utilized. p-Chloromercuribenzoate and N-ethylmaleimide inhibited the enzyme activity and reduced glutathione protected the enzyme from their inhibition. Choline and serine had no effect on the enzyme activity. The enzyme had a molecular weight of 44, 000 daltons as determined by gel filtration chromatography. Eggs contained the highest specific activity of the enzyme while adult insects had the highest total enzyme activity. 相似文献
5.
Qingqing Bi Baoqin Han Wanshun Liu Yilin Feng Zhongqing Jiang 《Biotechnology letters》2013,35(7):1115-1120
A new serine protease with fibrinolytic activity from a marine invertebrate, Urechis unicinctus, was purified to electrophoretic homogeneity using column chromatography. SDS-PAGE of the purified enzyme showed a single polypeptide chain with MW ~20.8 kDa. Its N-terminal sequence was IIGGSQAAITSY. The purified enzyme, UFEIII, was stable at pH 6–10 below 60 °C with an optimum pH of 8.5 at approx. 55 °C. The enzyme activity was significantly inhibited by PMSF and SBTI suggesting that it was a serine protease. In fibrin plate assays, UFEIII was contained 1.46 × 103 U (urokinase units) mg?1 total fibrinolytic activity, which consisted of 692 U mg?1 direct fibrinolytic activity and 769 U mg?1 plasminogen-activator activity. Km and Vmax values for azocasein were 1 mg ml?1 and 43 μg min?1 ml?1, respectively. 相似文献
6.
α-d-Galactosidases (α-d-galactoside galactohydrolase, EC 3.2.1.22) from normal coconut endosperm were isolated and partially purified by a combination of ammonium sulfate fractionation, SP-Sephadex C50–120 ion-exchange chromatography and Sephadex G-200 and G-100 gel filtration. Two molecular forms of the enzyme, designated as A and B, were eluted after SP-Sephadex C50–120 ion-exchange chromatography. α-d-Galactosidase A, which is the major isoenzyme, was partially purified 43-fold on Sephadex G-200 and has a MW of about 23 000 whereas α-d-galactosidase B was partially purified 23-fold on Sephadex G-100 and has a similar MW of about 26 600. Both isoenzymes exhibited optimum activity at pH 7.5. The apparent Km and Vmax of α-d-galactosidase A were obtained at 3.46 × 10?4M and 1.38 × 10?3 M p-nitrophenyl α-<d-galactoside, respectively. A distinct substrate inhibition was noted. The enzyme was inhibited strongly by d-galactose and to a lesser extent by myo-inositol, d-glucose-6-phosphate, l-arabinose, melibiose and iodoacetic acid. Similarly, makapuno α-d-galactosidase was localized in the 40–70 % (NH4)2SO4 cut but its optimum activity at pH 7.5 was considerably lower as compared to the normal. Its Km was obtained at 6.75 × 10?4 M p-nitrophenyl α-d-galactoside while the Vmax was noted at 5.28 × 10?3 M p-nitrophenyl α-d-galactoside. Based on the above kinetic data, the possible cause(s) of the deficiency of α-d-galactosidase activity in makapuno is discussed. 相似文献
7.
An inducible pyridine nucleotide-linked cyclohexanol dehydrogenase activity was present in crude extracts from aNocardia species following growth on cyclohexane. The enzyme was purified 126-fold by affinity chromatography and has an oligomeric
molecular weight of 145,000 ±5,000. There was an absolute requirement for NAD for activity and the products of the dehydrogenase
reaction were stoichiometric amounts of NADH and cyclohexanone. The enzyme had a broad specificity for secondary alcohols
including straight-chain secondary alcohols, cyclic and substituted cyclic alcohols, and cyclohexane diols. The apparentK
m
values for cyclohexanol and NAD were 3.7×10−5 M and 2.4×10−5 M, respectively, and the optimal pH for cyclohexanol oxidation was 10.5. The enzyme was heat sensitive, losing about 50%
activity after a 1-min incubation at 45°C. Enzyme activity was completely inhibited by the thiol agent,p-chloromercuribenzoate but not by metal chelating agents. 相似文献
8.
《Journal of Fermentation Technology》1986,64(3):219-225
d-Xylulose reductase (EC 1.1.1.9) from Pachysolen tannophilus IFO 1007 was purified by Sephadex G-100 gel chromatography with three columns and DEAE cellulose chromatography. The purified enzyme was entirely homogeneous on disc gel electrophoresis. It was most active at pH 9.1–10.0 and 55°C, and stable at pH 7–9 and below 25 °C. Its activity was stimulated by NH4Cl,NaCl,MgCl2,KCl, glutathione, cysteine and glycine, and inhibited remarkably by SH inhibitor such as lead acetate, HgCl2 and AgNO3. It oxidized xylitol, sorbitol, ribitol and glycerine but not mannitol, inositol, arabitol and erythritol. Its Km values of enzyme against xylitol, sorbitol and ribitol were 1.1 × 10−2 M, 3.0 × 10−2 M and 5.0 × 10−2 M, respectively. Its molecular weight was determined to be 120,000 by Sephadex G-200 column chromatography, and that of its subunit was 40,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. 相似文献
9.
Jagtar Singh Pradeep Kumar Navneet Batra Amit Joshi 《Journal of plant biochemistry and biotechnology.》2012,21(1):11-16
Peroxidases were isolated from Sapindus mukorossi (Reetha) and partially purified using acetone precipitation, ion-exchange chromatography with a 14-fold purification, 22% recovery and a specific activity of 266?×?103 units/mg protein. Sapindus peroxidases (SPases) showed six bands after acetone precipitation and one distinct band after ion exchange chromatography on Native-PAGE after zymography. Enzymes purified by ion exchange chromatography were loaded on Sepahdex G-50 superfine column and their molecular weight was reported to be 25?kDa. They showed temperature optima at 50°C and pH optima at 5.0.?km for SPases was reported to be 1.05?mM and 0.186?mM for guaiacol and H2O2 respectively. The Vmax/Km value for o-dianisidine was 449 while for H2O2 it was 5?×?105. Protocatechuic acid acts as a potent inhibitor for SPases (6.0% relative activity at 4.5???M) but ferulic acid inhibits its activity at a much lower concentration (0.02???M). Enzymes were stimulated by metal cations like Cu2+, Ca2+ (145, 168; percentage relative activity respectively) and showed mild inhibition (up to 20%) with Mn2+ and Mg2+. Alanine stimulated the enzyme activity (up to 33%; at 0?C100???M) while other amino acids like cysteine, methionine, tryptophan and tyrosine inhibited the SPases (13?C57% at 0?C100???M). 相似文献
10.
Y. Numata T. Nagatsu 《Journal of neurochemistry》1975,24(2):317-322
Approximately 80 per cent of tyrosine hydroxylase activity in bovine mandibular nerve and rabbit sciatic nerve was soluble, and the rest of the activity was particle-bound. The soluble enzyme in bovine mandibular nerve was isolated by ammonium sulphate fractionation (25–35 per cent saturation). The enzyme had a pH optimum at 5·9 in Tris-acetate buffer, and at 6·5 in Tris-HCl or phosphate buffer. The enzyme required a tetrahydropteridine cofactor. Km values toward various tetrahydropteridines such as l -erythro-tetrahydrobiopterin (a probable natural cofactor), 2-amino-4-hydroxy-6-methyltetrahydropteridine, and 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine were 2 × 10−5m , 5 × 10−5m and 4 × 10−4m , respectively. The Km value for tyrosine at 1 × 10−3m -2-amino-4-hydroxy-6-methyltetrahydropteridine as a cofactor was 5 × 10−5m . The enzyme activity was markedly stimulated with Fe2+ or catalase, but Fe2+ gave higher activity. The activity was inhibited with α, α′-dipyridyl, l -α-methyl-p-tyrosine, and various catecholamines. Among catecholamines, dopamine was the most potent inhibitor. l -5-Hydroxytryptophan was an inhibitor as potent as dopamine. Neither d -5-hydroxytryptophan nor 5-hydroxytryptamine inhibited the enzyme. The inhibition by l -5-hydroxytryptophan was partially competitive with tetrahydrobiopterin at concentrations higher than 9 × 10−5m , and partially uncompetitive at concentrations lower than 9 × 10−5m . The addition of heparin or lysolecithin did not affect enzyme activity with tetrahydrobiopterin as cofactor. 相似文献
11.
Scott D. Grover Pedro F. Canellas Randolph T. Wedding 《Archives of biochemistry and biophysics》1981,209(2):396-407
A procedure is described for purification of NAD malic enzyme (EC 1.1.1.39) to near homogeneity from potato tuber mitochondria. The purified enzyme is active with either NAD or NADP, and functions with either Mg2+ or Mn2+. Vapp is greatest when the enzyme is assayed with Mg2+ and NAD. When Mn2+ replaces Mg2+ the Vapp of the NAD-linked reaction decreases but the Km values for all substrates drop substantially. When NADP is used in place of NAD, the Vapp of the Mg2+-linked reaction decreases and the Km values for most substrates increase. The pH optimum of the enzyme depends on the metal ion and cofactor used and varies between 6.4 and 6.8. At pH 6.8, with saturating levels of Mg2+ and NAD, the turnover number of the enzyme is 37,000 min?1. The shape of the pH profile indicates the involvement of two to three protons in the activation of the enzyme, whereas only one proton is involved in the inactivation process. The molecular weight of the enzyme in the presence of 5 mm dithiothreitol and 2 mm MgCl2 is 490,000 as determined by gel filtration. A lower molecular weight form of the enzyme predominates in gel filtration at lower levels of dithiothreitol and in native gel electrophoresis. Sodium dodecyl sulfate gel electrophoresis of the enzyme reveals two main bands with molecular weights of 61,000 and 58,000, suggesting that the subunit stoichiometry of the high-molecular-weight form may be α4β4. However, given the possibility that the smaller subunit may be a proteolytic artifact, the enzyme may prove to be an octamer of identical subunits. 相似文献
12.
4-Coumarate:CoA ligase (EC 6.2.1.12) was isolated from 8-day-old cell suspension cultures of parsley (Petroselinum hortense Hoffm.) which had been irradiated with ultraviolet light for 15 h. The enzyme was partially purified by fractionation with MnCl2 and (NH4)2SO4 and by column chromatography on diethylaminoethyl cellulose, hydroxyapatite, and aminohexyl-Sepharose. A 90-fold increase in specific activity with an overall yield of 20% was achieved. Analytical gel electrophoresis indicated the occurrence of only one 4-coumarate:CoA ligase species in the final enzyme preparation. The enzyme was largely specific for 4-coumarate and other derivatives of cinnamic acid. 4-Coumarate had the lowest apparent Km and the highest values (1.4 × 10?5, m and 14.7 × 105 pkatal × m?1, respectively) of all substrates tested. Only the trans isomer of 4-coumarate was activated. The two cosubstrates, ATP and CoA, exhibited sigmoidal saturation kinetics, which were interpreted as indicating homotropic, allo-steric effects. A molecular weight of about 67,000 was estimated for 4-coumarate:CoA ligase. The substrate specificity of the enzyme was in agreement with its proposed function in flavonoid biosynthesis. 相似文献
13.
Armin R. Gemmrich 《Phytochemistry》1975,14(2):353-357
A soluble enzyme which converts proline to glutamic acid using NAD as coenzyme was isolated from young prothallia and spores of the fern Anemia phyllitidis. The purification was about 36-fold. The pH optimum is between 10·2 and 10·7; the Km for proline is 4·6 × 10−4 M and for NAD 3·4 × 10−4 M. There are no multiple forms of this enzyme, as proved by gel electrophoresis. 相似文献
14.
G M Rothe 《Archives of biochemistry and biophysics》1974,162(1):17-21
Two l-lactate dehydrogenase isoenzymes and one dl-lactate dehydrogenase could be separated from potato tubers by polyacrylamide-gel electrophoresis. The enzymes are specific for lactate, while β-hydroxybutyric acid, glycolic acid, and glyoxylic acid are not oxidized. Their pH optima are pH 6.9 for the oxidation and 8.0 for the reduction reaction.The Km values for l-lactate for the two isoenzymes are 2.00 × 10?2 and 1.82 × 10?2, m. In the reverse reaction the affinities for pyruvate are 3.24 × 10?4 and 3.34 × 10?4, m. Both enzymes have similar affinities for NAD and NADH (3.00 × 10?4; 4.00 × 10?4, and 8.35 × 10?4; 5.25 × 10?4, m).The dl-lactate oxidoreductase may transfer electrons either to NAD or N-methyl-phenazinemethosulfate. The Km values of this enzyme for l-lactate are 4.5 × 10?2, m and for d-lactate 3.34 × 10?2, m. Its affinity for pyruvate is 4.75 × 10?4, m. The enzyme is inhibited by excess NAD (Km = 1.54 × 10?4, M) and has an affinity toward NADH (Km = 5.00 × 10?3, M) which is about one tenth of that of the two isoenzymes of l-lactate dehydrogenase. 相似文献
15.
Noboru Sugiyama Hideo Shimahara Tetsuo Andoh Motoko Takemoto 《Bioscience, biotechnology, and biochemistry》2013,77(1):9-17
A crude enzyme preparation hydrolyzing konjac mannan was extracted from germinating konjac tubers, and purified by chromatography with DEAE-cellulose and alkali-swollen cellulose, and by gel-filtration on Sephadex G-100. The purified enzyme preparation showed optimal activity at pH 4.7, optimum temperature at 40°C. It was considerably stable at pH’s between 4.0 and 8.0, but inactivated rapidly by temperaters above 50°C. Hydrolysis of the mannan by this enzyme proceeded by typical random mechanism, and the rate was in agreement with an empirical equation, p=0.43 E0.77 to0.5. As the Km and Vmax values for mannan, 7.14×10-2(%)and 23.8×10-3 (ΔOD500nm) were obtained, respectively. 相似文献
16.
M. Sharma P. K. Chaurasia A. Yadav R. S. S. Yadav S. Yadava K. D. S. Yadav 《Russian Journal of Bioorganic Chemistry》2016,42(1):59-68
A laccase from the culture filtrate of white rot fungus Daedalea flavida MTCC-145 has been purified and characterized. The method involved concentration of the culture filtrate by ultrafiltration and an anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and native polyacrylamide gel electrophoresis (native PAGE) both gave single protein bands indicating that the enzyme preparation was pure. The molecular mass of the enzyme determined from SDS-PAGE analysis was 75.0 kDa. Purification fold was 21.5 while recovery of the enzyme activity was 11.52%. Using 2,6-dimethoxyphenol, diammonium salt of 2,2'-[azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid)] and 3,5-dimethoxy-4-hydroxybenzaldehyde azine as substrates, the Km, kcat, and k cat/K m values of the laccase were found to be 440 µM, 6.45 s–1, 1.47 × 104 M–1 s–1; 366 µM, 6.45 s–1, 1.76 × 104 M–1 s–1; and 226 µM, 6.45 s–1, 2.85 × 104 M–1 s–1, respectively. The pH and temperature optima were 4.5 and 50°C, respectively. The enzyme was most stable at pH 5.0 when exposed for 1 h. The purified laccase has yellow color and shows no absorption band around 610 nm characteristic of blue laccases. The enzyme transforms toluene and substituted toluenes to corresponding benzaldehyde and substituted benzaldehydes in the absence of mediator molecules with higher catalytic efficiency as compared to other known laccases. 相似文献
17.
A S Liacouras T Q Garvey F K Millar E P Anderson 《Archives of biochemistry and biophysics》1975,168(1):74-80
The initial velocity pattern has been determined for uridine-cytidine kinase purified from the murine mast cell neoplasm P815. With either uridine or cytidine as phosphate acceptor, and ATP as phosphate donor, the pattern observed was one of intersecting lines, ruling out a ping-pong reaction mechanism, and suggesting that the reaction probably proceeds by the sequential addition of both substrates to the enzyme to form a ternary complex, followed by the sequential release of the two products. This pattern was obtained whether the reaction was run in 0.01 m potassium phosphate buffer, pH 7.5, or in 0.1 m Tris-HCl, pH 7.2. When analyzed by the Sequen computer program, the data indicated an apparent Km of the enzyme for uridine of 1.5 × 10?4m, an apparent Km for cytidine of 4.5 × 10?5m, and a Km for ATP, with uridine or cytidine as phosphate acceptor, of 3.6 × 10?3m or 2.1 × 10?3m, respectively. The V was 1.83 μmol phosphorylated/min/mg enzyme protein for the uridine kinase reaction and 0.91 μmol for the cytidine kinase reaction. 相似文献
18.
The partial purification of shikimate dehydrogenase (SDH) from tomato fruit was achieved by precipitation with ammonium sulphate, and chromatography on DEAE-cellulose and hydroxyapatite. The enzyme has a MW of 73000, shows an optimum at pH 9.1 and Km values of 3.8 × 10?5 M and 1.0 × 10?5 M with shikimic acid and NADP as substrates. NADP could not be replaced by NAD. The tomato enzyme is competitively inhibited by protocatechuic acid with a Ki value of 7.7 × 10?5 M. On the other hand, cinnamic acid derivatives and 2-hydroxybenzoic acid were ineffective. At 50° for 5 min the SDH is inactivated by 85%. The activity was inhibited by pCMB and N-ethylmaleimide, suggesting a requirement for SH groups. The inactivation plot of oxidation by pCMB was biphasic, and NADP decreased the reactivity of sulphydryl groups to the reagent. The activation energy was found to be 14.2kcal/mol. The properties of the SDH are discussed in relation to the enzymes from other sources. 相似文献
19.
《Journal of Fermentation and Bioengineering》1994,77(5):557-561
NAD(P)H dehydrogenase was purified approximately 480-fold from Saccharomyces cerevisiae with 6.5% activity yield. The enzyme was homogeneous on polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 40,000–44,000 by gel filtration on Sephadex G-150 column chromatography and SDS-polyacrylamide gel electrophoresis. The Km values for NADPH and NADH were 7.3 μM and 0.1 mM, respectively. The activity of the enzyme increased approximately 4-fold with Cu2+. FAD, FMN and cytochrome c were not effective as electron acceptors, although Fe(CN)63− was slightly effective. NADH generated by the reaction of lactaldehyde dehydrogenase in the glycolytic methylglyoxal pathway will be reoxidized by NAD(P)H dehydrogenase. NAD(P)H dehydrogenase thus may contribute to the reduction/oxidation system in the glycolytic methylglyoxal pathway to maintain the flux of methylglyoxal to lactic acid via lactaldehyde. 相似文献
20.
W A Fenton A M Hack H F Willard A Gertler L E Rosenberg 《Archives of biochemistry and biophysics》1982,214(2):815-823
Methylmalonyl coenzyme A (CoA) mutase has been purified to apparent homogeneity from human liver by a procedure involving column chromatography on DEAE-cellulose, Matrex-Gel Blue A, hydroxylapatite, and Sephadex G-150. The overall purification achieved is 500- to 600-fold, yield 3–5%. Electrophoresis of the native purified protein on nondenaturing polyacrylamide gels shows a single diffuse band coincident with the enzyme activity; dodecyl sulfate/polyacrylamide gels show a single protein band with an apparent molecular weight of 77,500. The native protein has a molecular weight of approximately 150,000 by Sephadex G-150 chromatography, suggesting that it is composed of two identical subunits. The activity of the purified enzyme is stimulated only slightly (10–20%) by the addition of its cofactor, adenosylcobalamin, indicating that the purified enzyme is largely saturated with coenzyme. The spectrum of the enzyme is consistent with the presence of about 1 mole of adenosylcobalamin per mole of subunit. The enzyme displays complex kinetics with respect to dl-methylmalonyl CoA; substrate inhibition by l-methylmalonyl CoA appears to occur. The enzyme activity is stimulated by polyvalent anions (PO43? > SO42? > Cl?); monovalent cations are without effect, but high concentrations of divalent cations are inhibitory. The enzyme activity is insensitive to N-ethylmaleimide, is rapidly destroyed at temperatures > 50 °C, and shows a broad pH optimum around pH 7.5. 相似文献