Abstract
A qualitative study was made on the mechanism of dextran synthesis by dextransucrase. Enzymatic synthesis of dextran was experimentally studied with initial sucrose concentration from 50g/$\ell$ to 150g/$\ell$. The molecular weight distribution of synthesized dextran was measured by using on-line gel Permeation chromatographic system Sucrose was observed not to work as a primer within the range of concentration tested. At the initial sucrose concentration of 50g/$\ell$, dextran with molecular weight of medium range ($10^4-2{\times}10^6$) was synthesized due to the mass transfer limitation of sucrose. The amount of the dextran of medium range decreased with the initial sucrose concentration. Dextran was likely to be synthesized by radical chain polymerization mechanism since the dextran of medium range was not produced at higher sucrose concentrations.
본 연구에서는 dextransucrase의 효소반응에 의한 dextran 생성기작을 규명하고자 하였다. Dextransucrase에 의한 dextran 생성은 초기당농도 50~150g/$\ell$에 대하여 수행하였고 생성된 dextran은 GPC를 사용하여 분자량 분포를 측정하였다. 이 연구에서 실험한 surcrose 농도범위에서는 surcrose가 primer로 작용하지 않은 것으로 추측된다. 또한 surcrose 농도가 50~100g/$\ell$의 범위에서 확산에의한 surcrose의 물질전달 제약에 의한 중합속도의 감소로 먼저 중간분자량 dextran이 생성되었다가 고분자량 dextran이 생성된다는 것을 알 수 있었다. Surcrose 농도가 100~150g/$\ell$로 증가하면서 중간분자량 dextran 생성기작은 라디칼 중합반응을 따르나 낮은 surcrose 농도에서는 물질전달 제약에 의하여 중합반응속도가 감소되어 중간분자량의 dextran을 생성함을 알 수 있었다.
