TY - JOUR
T1 - Purification and characterization of 1-aminocyclopropane-1-carboxylate synthase from etiolated mung bean hypocotyls
AU - Tsai, De Sheng
AU - Arteca, Richard N.
AU - Bachman, Jeannette M.
AU - Phillips, Allen T.
N1 - Funding Information:
1 This work was supported by the Pennsylvania State University Agricultural Experiment Station Project No. 2809 and the College of Agriculture Intercollege-Interdisciplinary Research Project No. 2900. This is Contribution No. 121 of the Department of Horticulture, The Pennsylvania State University, and is authorized for publication as No. 7791 in the Journal Series of the Pennsylvania Agricultural Experiment Station. a To whom correspondence should be addressed. a Abbreviations used: AdoMet, S-adenosylmethionine; ACC, 1-aminocyclopropane-1-carboxylate;
PY - 1988/8
Y1 - 1988/8
N2 - 1-Aminocyclopropane-l-carboxylate (ACC) synthase, EC 4.4.1.14, was purified to homogeneity from etiolated mung bean hypocotyl segments. This was made possible by the ability to elevate the enzyme level markedly through hormone treatments and by stabilization of the enzyme with high phosphate concentrations. The four-step procedure resulted in 1050-fold purification with 25% yield, and consisted of stepwise elution from hydroxylapatite, chromatography on phenyl-Sepharose CL-4B, gradient elution from hydroxylapatite, and fast protein liquid chromatography (FPLC) on a MonoQ anion-exchange column. FPLC-purified ACC synthase migrated as a single band of Mr 65,000 on denaturing polyacrylamide gel electrophoresis. The molecular weight of native enzyme by Bio-Gel A-0.5 m chromatography was 125,000, indicating that the enzyme probably exists as a dimer of identical 65,000 Mr subunits. The mung bean ACC synthase exhibited a pH optimum of 8.0 for activity and a Km for S-adenosylmethionine (AdoMet) of 55 μm at 30 °C. It exhibited an Arrhenius activation energy of 12 kcal mol-1 degree-1 and was inactivated at temperatures in excess of 40 °C. The specific activity for pure ACC synthase was 21 μmol of ACC formed/mg protein/h when determined under optimal conditions with 400 μm AdoMet.
AB - 1-Aminocyclopropane-l-carboxylate (ACC) synthase, EC 4.4.1.14, was purified to homogeneity from etiolated mung bean hypocotyl segments. This was made possible by the ability to elevate the enzyme level markedly through hormone treatments and by stabilization of the enzyme with high phosphate concentrations. The four-step procedure resulted in 1050-fold purification with 25% yield, and consisted of stepwise elution from hydroxylapatite, chromatography on phenyl-Sepharose CL-4B, gradient elution from hydroxylapatite, and fast protein liquid chromatography (FPLC) on a MonoQ anion-exchange column. FPLC-purified ACC synthase migrated as a single band of Mr 65,000 on denaturing polyacrylamide gel electrophoresis. The molecular weight of native enzyme by Bio-Gel A-0.5 m chromatography was 125,000, indicating that the enzyme probably exists as a dimer of identical 65,000 Mr subunits. The mung bean ACC synthase exhibited a pH optimum of 8.0 for activity and a Km for S-adenosylmethionine (AdoMet) of 55 μm at 30 °C. It exhibited an Arrhenius activation energy of 12 kcal mol-1 degree-1 and was inactivated at temperatures in excess of 40 °C. The specific activity for pure ACC synthase was 21 μmol of ACC formed/mg protein/h when determined under optimal conditions with 400 μm AdoMet.
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U2 - 10.1016/0003-9861(88)90329-3
DO - 10.1016/0003-9861(88)90329-3
M3 - Article
C2 - 3401016
AN - SCOPUS:0024060216
SN - 0003-9861
VL - 264
SP - 632
EP - 640
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 2
ER -