enzymatic rate law for irreversible non-modulated non-interacting unireactant enzymes Briggs-Haldane rate law <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:0000025">kcat</n2:ci></n2:bvar> <n2:bvar><n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000505">Et</n2:ci></n2:bvar> <n2:bvar><n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000515">S</n2:ci></n2:bvar> <n2:bvar><n2:ci definitionURL="http://biomodels.net/SBO/#SBO:0000371">Km</n2:ci></n2:bvar> <n2:apply> <n2:divide /> <n2:apply> <n2:times /> <n2:ci>kcat</n2:ci> <n2:ci>Et</n2:ci> <n2:ci>S</n2:ci> </n2:apply> <n2:apply> <n2:plus /> <n2:ci>Km</n2:ci> <n2:ci>S</n2:ci> </n2:apply> </n2:apply> </n2:lambda> </n2:semantics> </n0:math> The Briggs-Haldane rate law is a general rate equation that does not require the restriction of equilibrium of Henri-Michaelis-Menten or irreversible reactions of Van Slyke, but instead make the hypothesis that the complex enzyme-substrate is in quasi-steady-state. Although of the same form than the Henri-Michaelis-Menten equation, it is semantically different since Km now represents a pseudo-equilibrium constant, and is equal to the ratio between the rate of consumption of the complex (sum of dissociation of substrate and generation of product) and the association rate of the enzyme and the substrate.