A Lineweaver-Burk double reciprocal plot indicated that the proso millet extract functioned as a mixed competitive and noncompetitive inhibitor
The results indicated that Sch B significantly dose-dependently inhibited rat hepatic microsomal CYP3A activity with [K.sub.i] value of 16.64 mg/kg and showed the characteristic of a noncompetitive inhibitor
. Oral administration of Sch B for 3 days in rats produced significant effect on the pharmacokinetics of oral midazolam.
Ketamine is thought to act as a noncompetitive inhibitor
of the N-methyl-D-aspartate (NMDA) receptor, which is part of the glutaminergic neurotransmitter system.
One of the metabolites, urolithin A, was the most potent uncompetitive inhibitor of CYP1B1 exhibiting two fold selectivity over CYP1A1, while another, urolithin B, was a noncompetitive inhibitor
with three fold selectivity.
Quenching-recovery experiments were also performed using "quenched" equimolar calcein-nickel(II) solutions and added catalase, in order to quantify binding between this important enzyme and the noncompetitive inhibitor
Dihydrotanshinone was a competitive inhibitor of human CYP1A2([K.sub.i] = 0.53 [mu]M) and CYP2C9([K.sub.i] = 1.92 [mu]M), a noncompetitive inhibitor
of CYP3A4 [K.sub.i] = 2.11 [mu]M) but an uncompetitive CYP2E1 inhibitor.
The noncompetitive inhibitors
increase [V.sub.max] values and do not change [K.sub.m] values against enzymes.
X-ray crystallographic analysis revealed that noncompetitive inhibitors
occupied and interacted with the enzyme active site or allosteric binding pocket ~20 [Angstrom] away from the catalytic site (helices [[alpha].sub.3], [[alpha].sub.6], and al) .