Cooperativity 2KIS]+2KK [S 1+2KS]+KK [S x(1+βx) Y 1+2x+βx β=K大/K X KISI B>1: positive cooperativity β>2: sigmoidal1 cur ve B< 1: negative cooperativity (always: dY/dx2< 0)Cooperativity 2 1 2x βx x(1 βx) Y 2 [S] * 1 2K[S] KK 2 [S] * 2K[S] 2KK r + + + = + + + = β = K*/K x = K[S] β > 1: positive cooperativity β > 2: sigmoidal curve β < 1: negative cooperativity (always: d2Y/dx2 < 0)