enzymatic rate law for reversible mixed activation enzymatic rate law for irreversible substrate activation <n0:math xmlns:n0="http://www.w3.org/1998/Math/MathML"> <n2:semantics xmlns:n2="http://biomodels.net/SBO/" definitionURL="http://biomodels.net/SBO/#SBO:0000062"> <n2:lambda> <n2:bvar> <n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000515"> substrate </n2:ci> </n2:bvar> <n2:bvar> <n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000324"> V </n2:ci> </n2:bvar> <n2:bvar> <n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000282"> Ksc </n2:ci> </n2:bvar> <n2:bvar> <n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000282"> Ksa </n2:ci> </n2:bvar> <n2:apply> <n2:divide /> <n2:apply> <n2:times /> <n2:ci> V </n2:ci> <n2:apply> <n2:power /> <n2:apply> <n2:divide /> <n2:ci> substrate </n2:ci> <n2:ci> Ksa </n2:ci> </n2:apply> <n2:cn> 2 </n2:cn> </n2:apply> </n2:apply> <n2:apply> <n2:plus /> <n2:cn> 1 </n2:cn> <n2:apply> <n2:divide /> <n2:ci> substrate </n2:ci> <n2:ci> Ksc </n2:ci> </n2:apply> <n2:apply> <n2:divide /> <n2:ci> substrate </n2:ci> <n2:ci> Ksa </n2:ci> </n2:apply> <n2:apply> <n2:power /> <n2:apply> <n2:divide /> <n2:ci> substrate </n2:ci> <n2:ci> Ksa </n2:ci> </n2:apply> <n2:cn> 2 </n2:cn> </n2:apply> </n2:apply> </n2:apply> </n2:lambda> </n2:semantics> </n0:math> This enzymatic rate law is available only for irreversible reactions, with one substrate and one product. There is a second binding site for the enzyme which, when occupied, activates the enzyme. Substrate binding at either site can occur at random.