I am reading a paper* about the link between the enzyme GSK3 and autism, and I have come across the following statement:
Unlike many kinases that require a signal to be activated, GSK3 is constitutively partially active; therefore, signals impinging on GSK3 can either decrease or increase its activity.
I am not sure what it means for an enzyme to be constitutively partially active, and I have tried Googling it but have not found any results. Any insights are appreciated.
* Mines MA, Yuskaitis CJ, King MK, Beurel E, Jope RS. GSK3 influences social preference and anxiety-related behaviors during social interaction in a mouse model of fragile X syndrome and autism. PLoS One. 2010;5(3):e9706.