the binding and the kinetic data , however , can be fitted by two diametrically opposed models of receptor to enzyme coupling : ( a ) the precouped enzyme-receptor model where activation of the enzyme occurs , according to the following scheme : formula ( see text ) where h is the hormone , re is the precoupled respetor-enzyme complex , k1 and k2 are the rate constants describing hormone binding , and k is the rate constant characterizing the formation of hre ' from the intermediate hre .
C0014442
enzyme
C0026741
enzyme complex