Bacillus sp. KJ16에서 Cyclodextrin Glucanotransferase와 Cyclodextriase 생산의 Catabolite Repression = Catabolite Repression of Cyclodextrin Glucanotransferase and Cyclodextrinase Syntheses in Bacillus sp. KJ16

국문 초록 (Abstract)

토양에서 분리한 CGTase와 CDase 생산균주 Bacillus sp. KJ16에서 이들 효소 생합성의 catabolite repression에 관해 조사하였다. 두 효소는 유도기질인 탄소원의 유무에 관계없이 균의 증식시기에 따라 생산되었으며, CGTase는 주로 배양초기 약 20시간 정도에 최대로 생산되고(약 60 mU/ml) CDase는 배양후 약 60시간에 최대치(약 18 mU/ml)를 나타내었다. 효소유도기질로는 amylopectin이 가장 좋았으며 기초배지에 첨가하였을 때 CDase의 생산은 약 6배 정도 증가하였으나 CGTase의 생산은 약 1.3배 정도의 증가에 그쳤다. 또 glucose와 같은 단당류에 의해서는 CGTase의 생산은 약간 억제를 받았으나 CDase의 생산은 완전히 억제되었다. Glucose에 의한 CDase 생산 억제효과는 glucose 농도에 비례하였으며 0.6% 이상에서는 완전히 효소생산이 억제되었다. Amylopectin의 농도별 CDase 유도 효과는 0.5%에서 약 14배로 가장 높았다. 또한, 10mM cAMP를 첨가한 배지에서 두 효소의 생산량은 증가하지 않았으며 2-deoxy-D-glucose와 3-O-methyl-D-glucopy-ranose와 같은 glucose analogue도 효소의 생산에는 영향을 미치지 않는다.

다국어 초록 (Multilingual Abstract)

The biosynthesis and catabolite repression of cyclodextrin glucanotransferase(CGTase) and cyclodextrinase(CDase) were studied in Bacillus sp. KJ16. In accompanying to the cell growth, CGTase was synthesized during early growth phase (20h culture) and CDse was synthesized during late growth phase (60h culture). Synthesis of CGTase was rather constitutive than that of CDase in the absence or presence o carbon source. Production of CDase was strongly stimulated by amylopetin and γ-CD medium (about 6 times), but CGTase synthesis was slightly increased (about 1.3 times). Easily metabolizable carbohydrates such as D-glucose, D-fructose and D-mannose completely repressed the expression of CDase, whereas their repressive effect to CGTase synthesis was relatively negligible. By addition of 10mM cAMP, any significant effect on the synthesis of the two enzymes was not observed. Hardly metabolizable glucose analogues such as 2-deoxy-D-glucose and 3-O-methyl-D-glucose has to be metabolized to exert its repressive effect. With these results, it seems likely that the biosynthesis of CGTase and CDase are regulated by the catabolite repression due to unknown metabolite(s) of EM pathway.