influenced by temp ((functional temp and optimum temp are different), pH, substrate (activity can increase until it reaches a maximum concentration, then there is no enzyme open and cannot increase rate), inhibitors (competitive and noncompetitive inhibitors, bind to the allosteric site, non is when an inhibitor is bound to site, changes shape of substrates active site and no rxn can occur, competitive inhition is when an inhibitor comes to the active site and not the allosteric site), denaturation is final, does not go back to being func, its when conditions go outside of functional range))