Lecture4-2009 - [S K m =[S if V = ½ V max cooperativity Reaction velocity(1 of active enzymes(2 catalytic effectiveness(3 affinity of enzymes

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Rate of Chemical Reactions (1) Reactant concentration (high conc b fast) (2) Temperature (=molecular motion) (3) Activation energy ( Δ G*, low b fast) (4) Presence of a catalyst (=enzyme) A + B C + D An example of enzyme action to support animal physiology b two amphibians with different jumping capabilities Leopard frog ( Rana pipiens ) Western toad ( Bufo boreas ) vs. Answer : LDH levels in leg muscles b for anaerobic ATP production
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Enzyme (=biological catalyst) – has the most important role in regulating chemical reactions Role of enzyme in this reaction b lower the activation energy of rxn b increase the velocity of rxn S b bb bb S* b b b P S b S* b P (+ Enz.) Activation energy, Δ G* = -2.3RT log ([S*]/[S]) = -2.3RT log K* Activation E. Enzymes, General Properties b h Specificity h h Allosteric modulation S + E b ES b P + E Specificity ligands Enzyme X Enzyme Y Active site Stable E-S complex
Background image of page 2
Enzyme Kinetics: Hyperbolic vs. Sigmoid Michaelis-Menton Eq b describes the kinetic behavior of enzymes. V = K m + [S] V max
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: [S] K m = [S], if V = ½ V max cooperativity Reaction velocity (1) # of active enzymes (2) catalytic effectiveness (3) affinity of enzymes Regulation of Cell Function by Enzymes 1. Control of enzyme synthesis 2. Control of enzyme activity degradation (i) allosteric modulation h Inducible enzymes (e.g. Cyt 450) ** End-product inhibition is also an example of allosteric modulation (ii) covalent modulation- protein kinases Aerobic and anaerobic metabolism Energy usage: Brain > Heart > some Skeletal M. > Kidney, Endocrine glands Energy generation Car vs. Living system 1 explosion CO 2 H 2 O Fuel O 2 Food CO 2 H 2 O h Metabolic pathway ATP: high energy intermediate for the cell adenine ribose Transfer of Chem E by coupled reactions R1) X + Pi b X-phosphate Δ Gº = +4.0 kcal/mol R2) ATP + H 2 0 b ADP + Pi Δ Gº = -7.3 kcal/mol Coupled rex ATP + X b ADP+ X-phosphate Δ Gº = -3.3 kcal/mol Is this rxn spontaneous?...
View Full Document

This note was uploaded on 03/11/2009 for the course BIOS 342 taught by Professor Tanda during the Spring '09 term at Ohio University- Athens.

Page1 / 4

Lecture4-2009 - [S K m =[S if V = ½ V max cooperativity Reaction velocity(1 of active enzymes(2 catalytic effectiveness(3 affinity of enzymes

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online