Purification and Characterization of Acetylcoenzyme A: Deacetylvindoline 4-O-acetyltransferase From Catharanthus Roseus

Arch Biochem Biophys. 1990 Jun;279(2):370-6. doi: 10.1016/0003-9861(90)90504-r.

Abstract

The enzyme acetylcoenzyme A:deacetylvindoline 4-O-acetyltransferase (EC 2.3.1.-) (DAT), which catalyzes the final step in vindoline biosynthesis in Catharanthus roseus, was purified 3300-fold using ammonium sulfate precipitation followed by gel filtration, anion exchange, hydroxyapatite, and affinity chromatographies. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the purified DAT showed the presence of two major proteins having Mr values of 33,000 and 21,000, whereas native PAGE showed three protein bands, and isoelectric focusing-PAGE one diffuse protein band (pI = 4.7-5.3) plus two minor protein bands (pI = 5.7 and 6.1). Purified DAT possessed Km values of 6.5 microM and 1.3 microM for acetylcoenzyme A and deacetylvindoline, respectively, and Vmax values of 12.6 pkat/microgram protein (acetylcoenzyme A) and 10.1 pkat/micrograms protein (deacetylvindoline). Inhibition of DAT by tabersonine, coenzyme A, and cations (K+, Mg2+, and Mn2+) was observed, while the pH optimum of this enzyme was determined to be 7.5 to 9.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyl Coenzyme A / metabolism*
  • Acetyltransferases / isolation & purification*
  • Acetyltransferases / metabolism
  • Cations / pharmacology
  • Chromatography, Affinity
  • Electrophoresis, Polyacrylamide Gel
  • Hydrogen-Ion Concentration
  • Isoelectric Point
  • Kinetics
  • Molecular Weight
  • Plants / enzymology*
  • Vinblastine / analogs & derivatives*
  • Vinblastine / metabolism

Substances

  • Cations
  • vindoline
  • Vinblastine
  • Acetyl Coenzyme A
  • Acetyltransferases
  • acetylcoenzyme A-deacetylvindoline 4-O-acetyltransferase