Lac operon (urgent) - (Nov/07/2001 )

Hi everybody,

while I was trying to regulate the expression of the b-galactosidase gene and monitoringthe resultant enzymatic activity, I found that enzymatic activity in a tube containing justglucose and and a bacterial strain was induced. I have used the ONPG (o-nitrophenyl-B-galactoside) as a coulerless substrate to be hydrolized by the b-galactosidase, but as you know when glucose is presentas th only carbon source there is no cAMP (cyclic andenosime monophosphate) to binf to the promoter andproduce b-galactosidase. Does anybody have an idea of how the enzymatic activity is produced ?

Thanks

Dear Mouti,

The experiment you are describing, is one I worked on some months ago. I also had an occasion where B-galactosidase was induced, while it shouldn't. The reason was I used an E. coli strain which had the regulator gene switched on all of the time. Perhaps that's the case. Also, ONPG will split automatically within some time, especially when placed in a hot environment. This usually takes hours up to a day.

Please let me know of the progress.

Kind regards,

Vincent GroenewoldBiotechnology studentthe Netherlands.