Dextran molecular size and degree of branching as a function of sucrose concentration, pH, and temperature of reaction of Leuconostoc mesenteroides B-512FMCM dextransucrase.
Reactions of Leuconostoc mesenteroides B-512FMCM dextransucrase with increasing concentrations of sucrose, from 0.1 to 4.0 M, gave a decreasing amount of high-molecular weight dextran (HMWD) (>10(6) Da) with a concomitant increase in low-molecular weight dextran (LMWD) (<10(5) Da). At 0.1 M sucrose, pH 5.5, and 28 degrees C, 99.8% of the dextran had a MW>10(6) Da and at 4.0 M sucrose, 69.9% had a MW<10(5) Da and 30.1% had a MW>10(6) Da, giving a bimodal distribution. The degree of branching increased from 5% for 0.1 M sucrose to 16.6% for 4.0 M sucrose. The temperature had very little effect on the size of the dextran, which was >10(6) Da, but it had a significant effect on the degree of branching, which was 4.8% at 4 degrees C and increased to 14.7% at 45 degrees C. Both the molecular weight (MW) and the degree of branching were not significantly affected by different pH values between 4.5 and 6.0.
Kim
Doman
D
Faculty of Applied Chemical Engineering and Engineering Research Institute, Chonnam National University, 300 Yongbong-Dong, 500-757, Gwangju, Republic of Korea. dmkim@chnnam.ac.kr
Robyt
John F
JF
Lee
So-Young
SY
Lee
Jin-Ha
JH
Kim
Young-Min
YM
D003911:Dextrans / Q000737:chemistry* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005964:Glucosyltransferases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis / Q000187:drug effects; D007934:Leuconostoc / Q000201:enzymology*; D008970:Molecular Weight; D013395:Sucrose / Q000494:pharmacology*; D013696:Temperature
D003911:Dextrans; D013395:Sucrose; D005964:Glucosyltransferases; C020025:dextransucrase