4.5 Enzymes.ppt

ENZYME

Enzymes

Are protein molecules made by living cells

Enzymes

Act as catalysts : speed up the rate of metabolic reaction

Enzymes

Not chemically changed at the end of reaction

General characteristics of enzymes

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

speed up the rates of biochemical reaction in the cells

speed up the rates of biochemical reaction in the cells

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

Only a small amount of enzyme is needed to catalyzed a lot of substrate

Only a small amount of enzyme is needed to catalyzed a lot of substrate

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

very specific – each class of enzyme will catalyze only one particular reaction

very specific – each class of enzyme will catalyze only one particular reaction

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

Not used up or destroyed in the reactions that they catalyse, but can be reused again

Not used up or destroyed in the reactions that they catalyse, but can be reused again

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

Catalyse reversible reactionCatalyse reversible reaction

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

Many enzymes are only able to work in the presence of a coenzyme (or cofactor)

Many enzymes are only able to work in the presence of a coenzyme (or cofactor)

General Characteristics Of EnzymesGeneral Characteristics Of Enzymes

Enzymes are affected by changes in temperature & pH

Enzymes are affected by changes in temperature & pH

Naming of enzymes

An enzyme is named by taking its substrate and adding the suffix ‘-ase’

Sucrose + water glucose + fructose

Types of Enzyme

TYPE OF ENZYMESTYPE OF ENZYMES

• Catalyses reactions within a cell• Formed on free ribosomes in the

cytoplasm

Intracellular EnzymeIntracellular Enzyme Extracellular Enzyme

• Leaves cell and catalyses reactions outside

• Synthesized on ribosomes attached to rough ER

Synthesized of extracellular enzyme

Mechanism of enzyme reaction

Enzyme substrate complex

Effect of pH on enzyme

Effect of temperature

The Uses of Enzyme

Application Enzymes used Uses

1 Dairy industry Rennin Coagulate milk proteins in cheese manufacturing

Lipase Used in the ripening of cheese

2 Fish industry Protease Removes the skin of the fish

3 Baking industry Amylase Breaks down of starch to glucose

Protease from microorganisms

Breaks down and lower proteins in flour for biscuit manufacture

4 Brewing industry

Amylase from germinating barley

Breaks down of starch to glucose for fermentation by yeast

Protease Breaks down of protein to amino acid for yeast

Removes cloudiness during the storage of beers

Application Enzymes used Uses

5 Biological detergents

Protease, lipase and amylase

Removes organic stains (blood, food, saliva) from clothes

Amylase Removes resistant starch residues

6 Leather tanning industry

Protease Removes hair from animal hides and make leather softer

7 Textile industry Amylase Removes starch that is applied to threads to prevent damage during wearing

8 Processing food Trypsin To pre-digest some baby foods

Amylase Converts starch to glucose syrup

9 Paper industry Amylase Partial breakdown of starch to fill the gaps between fibres to produce smoother paper

10 Medical analysis Trypsin Removes blood clots and cleans wounds