Purification and properties of versiconal cyclase from Aspergillus parasiticus.
Versiconal cyclase catalyzes the dehydration of versiconal to versicolorin B or versicolorin C [versicolorin B(C)]. The enzyme was purified from mycelia of Aspergillus parasiticus by DEAE-cellulose, hydroxylapatite, and Mono Q column chromatography. The protein contains two identical subunits of molecular weight 72,000 per molecule of native protein. The pI of the enzyme is 3.95. The pH activity curve had a broad maximum with a peak at 5.5. The Km and Vmax for versiconal at 30 degrees C and pH 6.0 are 3.1 microM and 0.15 mumol min-1mg-1, respectively. Most of the formation of versicolorin B(C) in the cell is attributed to the action of versiconal cyclase.
Lin
B K
BK
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409.
Anderson
J A
JA
D000348:Aflatoxins / Q000096:biosynthesis*; D000880:Anthraquinones / Q000378:metabolism*; D001230:Aspergillus / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D006836:Hydro-Lyases / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight
D000348:Aflatoxins; D000880:Anthraquinones; C009653:versiconal; D006836:Hydro-Lyases; C072282:versiconal cyclase