Uncompetitive inhibition inhibitor binds to the

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Unformatted text preview: ition on second line I Note the position of the “α” in the two new equations! Uncompetitive Inhibition Inhibitor binds to the enzyme-substrate complex, not to the free enzyme. K’I is the quantity of interest: it captures the inhibition power of inhibitor I for the particular reaction catalyzed. K’i = [ES][I] / [ESI] (VVP Eq. 12-34) Hence: the SMALLER the K’i, the BETTER the inhibitor! Here: I = Uncompetitive Inhibitor S = Substrate E = Enzyme ES = Michaelis complex ESI = Enzyme-Substrate-Inhibitor Complex P = Product Uncompetitive Inhibition MM equation: v = Vmax[S]/(KM + α‘[S]), Where α' = (1 + [I]/K'I) and K'I = [ES][I]/[ESI]. LB equation: 1/v0 = (KM /Vmax) (1/ [S]) + α’/ Vmax VVP 4e Fig 12-9 Lineweaver-Burk Plot for Uncompetitive Inhibition: PARALLEL LINES!! With intersection points 1/v0= α’/Vmax on the vertical axis; Since Vmax is known, α’ can be calculated; And from α’, K’I can be calculated using the definition of α’ Michaelis-Menten and Lineweaver-Burk Equations # 3 Uncompetitive Inhibition on last line I I Note the “α-prime”-s in the last line of the Table! (α-prime = α’ = defined underneath the Table, and also in previous slide) Mixed (noncompetitive) Inhibition Inhibitor binds to both the enzyme-substrate complex and the free enzyme. Here: I = Inhibitor S = Substrate E = Enzyme ES = Michaelis complex EI = Enzyme-Inhibitor Complex ESI = Enzyme-Substrate-Inhibitor Complex P = Product Mixed (noncompetitive) Inhibition VVP 4e Fig 12-10 Lineweaver-Burk Plot for Mixed (noncompetitive) Inhibition: Remember: No parallel lines, no intersection on point ON y-axis.. No need to remember any equation for a special point or a slope of a line from this slide. Michaelis-Menten and Lineweaver-Burk Equations # 4 Mixed (Noncompetitive) Inhibition on last line I I No need to remember equations from the lowest line inside the Table (about Mixed inhibition) Drug Design A case study Structure-Based Inhibitor Design of the enzyme GAPDH from the sleeping sickness parasite, a “Trypanosomatid”. Sleeping Sickness a.k.a “African trypanosomiasis” Blood stream form of parasite Tsetse fly Lumbar puncture...
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