. "One model ( the direct inhibition model) describing the inhibition of the APC/C during the mitotic spindle checkpoint suggests that the association of the hBUBR1:hBUB3:MAD2*:CDC20 mitotic checkpoint complex (MCC) with APC/C results in the inactivation of APC/C. The affinity between MCC and APC/C is not high, thus inhibition is readily reversible when the mitotic spindle checkpoint has been satisfied."^^ . . .