Enzymes

B. Factors that affect Enzymes activity temperature, pH, substrate:

-change that affect protein structure also affects an enzymes catalysts function.

When enzymes is denatured → activity will be lost

Strong acid

Bases

Organic solvents decrease an enzymes catalyzed rate ofreaction.

Mechanical action

High temperature

Slight changes in pH - more effect on enzyme catalysts

• Some amino acid that make up enzyme have chains whose charge depends on pH.

Example:

side chains with carboxylic acid functional groups maybe either neutral or negatively charged, those

with amino groups maybe neutral or positively charge.

- As the pH changes the charges on an enzyme(active side of an enzymes)

- also change, because the enzyme catalysts is affected.

- For each enzyme, there is an optimal pH; shifts to more acidic or more basic condition decrease

the enzyme activity.

More acidic ENZYME

more basic ACTIVITY

Body temperature

-carefully controlled partly because enzymes activities are particularly temperature sensitive.

very low temperatures

High temperature

- Few reactant molecules have enough energy

to overcome the activation energy barrier and

the reaction occurs slowly.

More reactants have necessary activation energy,

and the rate increase (but a point is reached where

very high temperature causes enzyme denaturation

and the rate of reaction starts to decrease.

* Optimal temperature of many human enzymes is approximately about 37 °C –body temperature.

*not all enzymes operate optimal around the physiological temperature (37°C) and ph (7).

Alcalase ,Savinase -55°C warm water washes

Savinase- has a better pH optimum for detergent powders which commonly have pH around 9-10.

Alcalase- has a optimum of about 8, which is better adapted for liquid soaps.

Esperase – is frequently used in industrial or institutional laundries.

* This enzymes remain active at temperatures up to 70°C and a pH of 12.