원문정보
초록
영어
Leuconostoc citreum produces dextransucrase (sucrose: 1, 6-α-D-glucan 6-α
-D-glucosyltransferase EC 2.4.1.5) when induced with sucrose and the enzyme synthesizes dextran using sucrose as substrate. For overproduction of dextran-free dextransucrase, a mutant strain elaborating constitutive dextransucrase is required. For this, we developed a novel selection method of mutant strain using PNPG (p-nitrophenyl α-D-glucopyranoside) as substrate
analogue. After chemical mutagenesis by ethyl methane sulfonate, the constitutive mutants showed yellow halos around colonies on glucose agar plates. The dextransucrase activites were colorimetrically measured by production of p-nitrophenol from PNPG. According to this selection method, we have screened several mutant strains showing higher dextransucrase activities than the hoststrain when cultured on glucose medium. This method is sensitive
and rapid in handling a large number of mutant samples and therefore it can be easily applicable to mutation studies of various glycosyltransferases.