Of course! Never even try to do that. You will absolutely get electrocuted and may harm yourself seriously if you touch live terminal of an isolation transformer in operation.
And not just in the case of an isolation transformer, you will get electrocuted with any live terminal or conducting part. And voltage is not the correct measure of electrocution or electric shock, it is the current that is forced through the body. Any amount of current greater than 10 mA can be painful and that more than 100 mA can be lethal (sufficient to cause death). And we can not predict the severity of electric shock knowing just the voltage because actual resistince of the body varies very widely depending upon the points of contact and the skin condition (wet, moist or dry).