Enzymes: Michaelis-Menten Kinetics, Reaction Velocity | PDF
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Jason Ryan
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This document presents an exploration of enzymes, discussing topics such as enzymatic reactions and Michaelis-Menten kinetics. The document provides explanations on key concepts like reaction velocity, substrate binding, and the Michaelis constant, employing graphical representations to illustrate these biochemical principles.
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AfraTafreeh.com Enzymes Jason Ryan, MD, MPH Enzymatic Reactions P S AfraTafreeh.com E S + E ⇄ ES ⇄ E + P AfraTafreeh.com Enzymatic Reactions S + E ⇄ ES ⇄ E + P...
AfraTafreeh.com Enzymes Jason Ryan, MD, MPH Enzymatic Reactions P S AfraTafreeh.com E S + E ⇄ ES ⇄ E + P AfraTafreeh.com Enzymatic Reactions S + E ⇄ ES ⇄ E + P Image courtesy of Wikipedia/U+003F Michaelis-Menten Kinetics V = Reaction velocity Rate of P formation Vmax AfraTafreeh.com V = Vm* [S] Km + [S] V [S] AfraTafreeh.com Michaelis-Menten Kinetics Adding S → More P formation → Faster V Eventually, reach Vmax Michaelis-Menten Kinetics At Vmax, enzymes saturated (doing all they can) Only way to increase Vmax is to add enzyme AfraTafreeh.com AfraTafreeh.com Enzyme Kinetics Vmax More Enzyme Vmax [S] Michaelis-Menten Kinetics V = Reaction velocity Rate of P formation Vmax AfraTafreeh.com V = Vm* [S] Km + [S] V [S] AfraTafreeh.com Michaelis Constant (Km) V = Vm * [S] Km + [S] Key Points: 1. Km has same units as [S] 2. At some point on graph, Km must equal [S] Michaelis Constant (Km) V = Vm * [S] = Vm * [S] = Vm [S] + [S] 2 [S] 2 AfraTafreeh.com When V = Vm/2 [S] = Km AfraTafreeh.com Michaelis Constant (Km) Vmax V = Vm* [S] Vmax/2 Km + [S] Km [S] Michaelis Constant (Km) Small Km → Vm reached at low concentration [S] Large Km → Vm reached at high concentration [S] Vmax AfraTafreeh.com V = Vm* [S] Vmax/2 Km + [S] Km [S] AfraTafreeh.com Michaelis Constant (Km) Small Km → Substrate binds easily at low [S] High affinity substrate for enzyme Large Km → Low affinity substrate for enzyme Vmax V = Vm* [S] Vmax/2 Km + [S] Km [S] Key Points Km is characteristic of each substrate/enzyme Vm depends on amount of enzyme present Can determine Vm/Km from Michaelis Menten plot V vs. [S] Lineweaver Burk plot 1/V vs. 1/[S] AfraTafreeh.com AfraTafreeh.com Lineweaver Burk Plot V = Vm* [S] Km + [S] 1 = Km + [S] = Km + [S] V Vm [S] Vm [S] Vm[S] 1= C *1 + 1 V [S] Vm Lineweaver Burk Plot 1 V Km Vm AfraTafreeh.com 1 Vm 1 S -1 Km
