1-Naphthyl Acetate Esterase Activity from Cultures of the Symbiont Yeast of the Cigarette Beetle (Coleoptera: Anobiidae)

Abstract

The 1-naphthyl acetate esterase activity from the cell-free preparation of cultures of the yeast-like symbiont, Symbiotaphrina kochii Jurzitza ex. W. Gams and v. Arx, of the cigarette beetle, Lasioderma serricome (F.), was investigated with isoelectric focusing, gel filtration chromatography, selective inhibition, and temperature and solvent stability studies. Gel filtration indicated that activity was predominantly due to one enzyme (or closely related enzyme forms) with a molecular weight of approximately 38,000. The isoelectric point of most of the activity ranged from pH 4.6 to 4.8. The presence of three bands in this region suggested that isoenzymes were present. The apparent Km for the symbiont esterase was 114 μM and the Vmax was 8.9 nmole/rnin/mg protein. The symbiont esterase was relatively resistant to acetone, sensitive to temperature treatments, and partially inhibited by relatively high concentrations of organophosphates and thiol reagents, but not by chelators.