PMID- 16349476
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20100708
LR  - 20200727
IS  - 0099-2240 (Print)
IS  - 1098-5336 (Electronic)
IS  - 0099-2240 (Linking)
VI  - 64
IP  - 1
DP  - 1998 Jan
TI  - Purification and Characterization of O-Methyltransferase I Involved in Conversion 
      of Demethylsterigmatocystin to Sterigmatocystin and of 
      Dihydrodemethylsterigmatocystin to Dihydrosterigmatocystin during Aflatoxin 
      Biosynthesis.
PG  - 166-71
AB  - O-Methyltransferase I, which catalyzes conversions both of 
      demethylsterigmatocystin (DMST) to sterigmatocystin (ST) and of 
      dihydrodemethylsterigmatocystin (DHDMST) to dihydrosterigmatocystin (DHST) during 
      aflatoxin biosynthesis, was purified to apparent homogeneity from the cytosol 
      fraction of the mycelia of Aspergillus parasiticus NIAH-26 through the following 
      chromatography series: phenyl-Sepharose, DEAE-Sepharose, phenyl-Sepharose, 
      Sephacryl S-300, and Matrex gel Green A. The apparent molecular mass was 
      estimated at 150 kDa based on Sephacryl S-300 gel filtration chromatography, and 
      the denaturing molecular mass was 43 kDa based on sodium dodecyl 
      sulfate-polyacrylamide gel electrophoresis. The pI of the enzyme was 4.4, and the 
      optimal pH for activity was broad, from 6.5 to 9.0. In competition experiments 
      using the purified enzyme, the formation of ST from DMST was suppressed when 
      DHDMST was added to the reaction mixture and DHST was newly formed. These results 
      indicate that DMST and DHDMST commonly serve as substrates for the enzyme. The 
      K(m) of the enzyme for DMST was 0.94 muM, and that for DHDMST was 2.5 muM. 
      Interestingly, MT-I kinetics deviated substantially from standard 
      Michaelis-Menten kinetics, demonstrating substrate inhibition at a higher 
      substrate concentration.
FAU - Yabe, K
AU  - Yabe K
AD  - National Institute of Animal Health, Tsukuba, Ibaraki 305, and Faculty of 
      Agriculture, Tottori University, Tottori 680, Japan.
FAU - Matsushima, K
AU  - Matsushima K
FAU - Koyama, T
AU  - Koyama T
FAU - Hamasaki, T
AU  - Hamasaki T
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Appl Environ Microbiol
JT  - Applied and environmental microbiology
JID - 7605801
PMC - PMC124688
EDAT- 2005/12/14 09:00
MHDA- 2005/12/14 09:01
PMCR- 1998/01/01
CRDT- 2005/12/14 09:00
PHST- 2005/12/14 09:00 [pubmed]
PHST- 2005/12/14 09:01 [medline]
PHST- 2005/12/14 09:00 [entrez]
PHST- 1998/01/01 00:00 [pmc-release]
AID - 0588 [pii]
AID - 10.1128/AEM.64.1.166-171.1998 [doi]
PST - ppublish
SO  - Appl Environ Microbiol. 1998 Jan;64(1):166-71. doi: 
      10.1128/AEM.64.1.166-171.1998.