Rate of Enzymatic Activity of Salivary Amylase based on changes in

temperature and pH Amurao Carreon Duldulao

Gonzales, A. 3Bio4

Catalyst

a substance that causes or accelerates a chemical reaction without being used up.

Enzymes Biological molecules that catalyze many important reactions

inside the body

Act as biological catalysts cause or accelerate chemical reactions by lowering the Energy of Activation (Ea )

Important biological reactions catalyzed by enzymes: Metabolism DNA synthesis RNA synthesis Protein synthesis Digestion

Properties of Enzymes

Large protein molecules Re-usable Remain unchanged Very specific- act only on specific substrate Operate at very high speeds Rate of reaction is dependent upon temperature, pH,

[E], & [S] Usually work best below 60C Denature at very high temperatures (e.g. 100C)

Properties of Enzymes

Active site

- pocket or cleft - contains amino acid side chains that participate in

substrate binding and catalysis

Substrate

- reactant molecules

Lock and key model

Emil Fischer

The active site and the substrate have complementary shapes to allow perfect fit

Right-sized key (substrate)

Keyhole (active site)

Lock (enzyme)

Induced fit (hand-and-glove) model

Daniel Koshland

The enzyme is assumed to be a flexible molecule

Binding of he substrate induces a conformational change in the enzymes active site resulting in a perfect fit

How enzymes work?

How enzymes work?

All chemical reactions have energy barrier of the free energy of activation

Increases the rate of reaction

How enzymes work?

Lowers the free energy of activation

Low free energy of activation more energized molecules faster rate of reaction

Salivary amylase

Secreted by salivary glands functions as the first main step of the process of

digestion catalyses the breakdown of starch into simpler

sugars (maltose and isomaltose) digests starch by catalyzing hydrolysis Optimum temperature : 37C Optimum pH : 5.6 6.7

Starch

Mixture of two polysaccharides: amylose and amylopectin

White, tasteless, solid carbohydrate

Converted to glucose through hydrolysis

Detected by iodine (blue-black color)

Objectives:

to examine the effect of different

temperatures on the enzymatic activity of the

salivary amylase

to examine the effect of different pH on the

enzymatic activity of the salivary amylase;

Salivary Amylase -Amylase Hydrolyzes alpha bonds of large, alpha linked

oligosaccharides and polysaccharides acts on linear (1,4) glycosidic linkages

STARCH + SALIVARY AMYLASE -> MALTOSE + SALIVARY AMYLASE + DEXTRIN

Salivary Amylase

chloride-dependent enzyme

AMY1A gene

Encodes human salivary amylase

Influence salivary amylase concentration and enzymatic activity

Effect of Temperature Increase in temperature = Faster enzymatic reaction

BUT... Enzymes work best at a certain temperature (optimum

temperature) wherein the reaction rate will be at a maximum

Optimum Temperature: 37 C (body temperature) Lower than 37 C = slower reaction At 40 C = some enzymes are denatured At 50 C and higher = most enzymes are denatured

Destruction of 2 and 3 structures

Effect of Temperature

Effect of pH pH affects the detailed structure of the active

site of the enzyme

Requires certain level of acidity and alkalinity

Not too much nor too little H+, which

interferes with electric charges and disrupts

H-bonds

Extremely high or low pH will result in the

complete loss of enzymatic activity

Effect of pH

Optimum pH: pH 6.7 7 (for groups 1-5),

pH 5.6 (for groups 6-10)

pH 10 is when most if not all enzymes are

denatured

Effect of temperature on Enzymatic activity

Increase in temperature, faster enzymatic reaction

Enzymes work best at a certain temperature (optimum temperature) wherein the reaction rate will be at maximum

Optimum temperature = 37C

Effect of pH on Enzymatic activity

Affects the ionization of acidic or basic amino groups

Affects the shape of the substrate in the same way

Optimum pH for salivary amylase: pH = 5.6-7