Inhibitors are compounds that decrease an enzymes activity Irreversible inhibitors Cin activators react with enzyme One inhibitor molecule can permanently shut off one enzyme molecule max Often powerful toxins can also be used as drugs Competitive Inhibition competes with substrate for binding Binds active site Does not affect catalysis Reversible Inhibitors bind 10 and can dissociate from enzyme a z CI No change In Vmax apparent Increase in 14M often structural analogs of substrates or products 1 Line Weaver Burk lines intersect at they axis No inhibitor c m m c s Es up I El Un Competitive Inhibition only binds to ES complex q Does not affect substrate binding and Inhibits catalytic function Decrease in Vmax apparent decrease in kna No change in km Vmax Line Weaver Burk lines are parallel Enzyme Allosteric Regulation Binding of a molecule to a different location from active site causes changes in enzymatic activity either 4 orcs 4 or activity of enzyme Often used as drugs to slow down a specific enzyme can bind 10 free enzyme prevents binding of the substrate Enzyme substrate complex prevents reaction Ets Es El P Est 9 Non Competitive Inhibition Binds enzyme with or without substrate Binds 10 regulatory site canister d Inhibits both substrate binding catalysis Decrease in Vmax apparent change In Km Line Weaver Burk lines intersect left from the y axis Lb GY s ma UH a s i Noncompetitive inhibitors are mixed inhibitors no change in km substrate Allosteric Inhibition binding of a molecule to allosteric site causes a shape change that reduces the affinity of the enzyme for the substrate End product inhibition substrate site G cid 15483 0 t modulator Substrate Allosteric activator conformational change that 4 affinity of an enzyme for the substrate cid 15483 cid 15483 cid 15483 cid 15483 cid 15483 Less active enzyme D d More active enzyme binds for chemical complex instead Of Inhibitor chemical reaction Is carried out end product produced too much end product excess binds to the allosteric site changes the shape of the substrate bind site substrate no longer binds stops metabolic pathway binding Allosteric reaction Ste s binding site 1 1 y Inhibitor binds 1 4 substrate substrate substrate 1 Non Competitive Competitive Inhibition substrate enzyme INHIBITOR inhibitor site binding g site gg nga gg h1b same s b Z fits binding g shape compete e E end product Binding of inhibitor causes to enzyme reaction IS not carried substrate binding site substrate to change shape without inhibitor can bind causes chemical not carried out reaction 10 be carried out product produced Allosteric Regulation kinetics Differs from Michealis Menten kinetics s mM cid 15483 Fiona c Ty R state Imai Kos s g gmK inhibitor Enzyme iq site Inhibitor v substrate binding Rtd 2 substrate binding 5 g Ggg Cf 64bInd independently enzyme undergoing nd at anytime The inhibitor and substrate Completing reaction LA um ma na by inhibition g ward