Effect of Temperature

Enzymes Part II:

Factors that Affect EnzymesFactors that Affect Enzyme Activity (Rate of Reaction):

Environmental Conditions

Cofactors and Coenzymes

Enzyme Inhibitors

Enzyme Concentration

Substrate Concentration1. Environmental ConditionsA. Effect of TemperatureSpeed of reaction increases until an Optimum temperature is reachedOptimum temperature is the temperature at which the enzyme works bestAfter this point the rate of reaction decreases until there is no reactionAt this point enzyme is said to be DENATURED active site destroyedHigh temperatures are the most damaging to proteins/enzymes. (Cooking denatures proteins)

1. Environmental ConditionsA. Effect of Temperature

Optimum temperature can be determined by graphing enzyme activity vs. T

The peak indicates the optimum temperature of the enzyme.1. Environmental ConditionsA. Effect of Temperature

Optimum temperature can be determined by graphing enzyme activity vs. T

Which enzyme is more likely to be found in the human body?

Enzyme AEnzyme BEnzyme CMost enzymes have an optimum pH of 7H+ and OH- ions affect bonding b/w R groups = CHANGES THE SHAPE OF THE ENZYME!!!!!Some enzymes have a different optimum pH Ex. pepsin (protease in stomach) has an optimum pH of 2

Why do you think pepsins optimum pH is 2?

1. Environmental ConditionsB. Effect of pH1. Environmental ConditionsB. Effect of pH

Optimum pH can be determined by graphing enzyme activity vs. pH

The peak indicates the optimum pH of the enzyme.

1. Environmental ConditionsB. Effect of pH

Optimum pH can be determined by graphing enzyme activity vs. pH

What is the optimum pH of:Pepsin?Amylase?Trypsin?

1. Environmental ConditionsC. Effect of Ion concentration (salts)

High ion concentrations can affect the charge of R side chains in proteins and enzymes

The changing shape changes the enzymes activity.

Optimum ion concentration can be determined by graphing enzyme activity vs. ion concentration

What is the optimum ion concentration of this enzyme?1. Environmental ConditionsC. Effect of Ion concentration (salts)2. Cofactors and CoenzymesA. Cofactors

Inorganic substances such as atoms of zinc, iron, or copperAffect enzyme activity. Enzyme might not work without them!

B. CoenzymesIf the cofactor is an organic molecule.Usually made from vitamins

2. Cofactors and CoenzymesGold, Iron, Zinc, Calcium ions, etc.Vitamins, and other organic moleculesC. Enzyme Inhibitorsinhibitor - a chemical that interferes with an enzymes activity.A. Competitive Inhibitor- resembles normal substrate- competes for the active site- Blocks the substrate from entering and thereby prevents the enzyme from acting.

B. Non-competitive inhibitorsDoes not enter the active siteInstead binds to enzyme somewhere else.Changes the shape so the substrate no longer fits

Competitive vs. Non-competitive inhibitor graphEventually, the substrate outnumbers the competitive inhibitor

But the non-competitive inhibitor will always lock up the same amount of enzyme

4. Enzyme Concentration

When substrate concentration is in excess amounts the concentration of enzyme limits the reaction speed

4. Enzyme Concentration

But eventually, the is not enough substrate for the enzyme to GO ANY FASTER!

5. Substrate Concentration

As more substrate is added eventually a saturation point is reached