Regulation of $\beta$-galactosidase Biosynt hesis in Lactobacillus sporogenes

Lactobacillus sporogenes에서$\beta$-galactosidase 생합성 조절

Regulation of $\beta$ -galactosidase formation was studied with Lactobacillus sporogenes. Synthesis of the enzyme was effectively induced by isopropyl- $\beta$-D-thiogalactopyranoside (IPTG) or galactose, and to a much lower level by lactose. When 15 mM glucose was added at the different intervals to the cultures that had been in contact with IPTG, the same levels of inhibition of the enzyme synthesis were observed (approximately one-third the differential rate of a control culture without glucose). This suggests that glucose did not interfere with the entry of the inducer into the cells, but interfere with the formation of $\beta$ -galactosidase through catabolite repression. The glucose inhibitory effect was not overcome by adding CAMP or cGMP to the culture media.

Lactobacillus sporogenes에서 Beta-glactosidase의 생합성은 isopropyl-Beta-galactopyransoide(IPTG)나 galactose에 의해 효과적으로 유도되었으며 배양초기에는 lactose에 의해서도 훨씬 낮은 정도로 유도되었다. Glucose는 inducer exclusion이나 transient repression이 아니 catabolite repression에 의해 Beta-galactosidase의 합성을 억제시킴을 알 수 있었다. 또한, glucose에 의한 Beta-galactosidase의 catabolite repression은 cAMP나 cGMP에 의해 전혀 완하되지 않았다.