Purification and Characterization of Myristoyl-Acyl Carrier Protein Thioesterase from Iris tectorum

  • Kang, Han-Chul (Grape Experiment Center, Rural Development Administration) ;
  • Cho, Kang-Jin (Department of Biochemistry, National Institute of Agricultural Science and Technology, Rural Development Administration) ;
  • Hwang, Young-Soo (Department of Biochemistry, National Institute of Agricultural Science and Technology, Rural Development Administration)
  • Published : 1998.06.30

Abstract

The myristoyl-acyl carrier protein (ACP) specific thioesterase from Iris tectorum was purified to a considerable homogeneity and characterized. The enzyme was eluted with a considerable stability by double-gradients using Triton X-100 and low ionic KCl or Na-phosphate through DEAE-52, Octyl-Sepharose, Q-Sepharose, and hydroxyapatite chromatoraphy. SDS-PAGE analysis showed a single band of 39 kDa. The native molecular weight was estimated to be 82 kDa by Sephacryl S-200 chromatography, indicating that the enzyme was a dimer. The thioesterase showed a chain-length specificity to myristoyl-ACP in preference to other-ACPs. The enzyme activity decreased by 1.0 mM myristate to about 27% of the original activity, whereas the remaining activity with decanoate was about 90%. The purified thioesterase was inhibited by myristoyl-CoA more than by myristate, suggesting that the myristoyl-AGP thiolesterase might be controlled by myristic acid and/or a subsequent product myristoyl-CoA. In addition, some biochemical characteristics of the enzyme were described.

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