B2.5 - Enzymes

Enzymes are biological catalysts.

They speed up chemical reactions without being used up in the process.

Enzymes are protein molecules, made from amino acids.

These are joined together in a long structure, folded in a 3D shape.

An enzyme's structure is determined by its sequence of amino acids & the bonds between its molecules.

ONLY MOLECULES W/ RIGHT SHAPE WILL BIND + REACT W/ ENZYME = SUBSTRATE MOLECULES.

Substrate molecules bind to the enzyme's active site.

enzyme + substrate --------------> e.s complex

When an enzyme denatures, there is a permanent change of the active site's shape.

Digestive enzymes are produced by specialised cells in glands + lining of gut.

The enzymes:

-pass from cells to digestive system

-meet food molecules

-catalyse breakdown of large food molecules

Different enzymes work best at different pH values.

Stomach produces hydrochloric acid. Enzymes in stomach work effectively in that environment.

Bile stored in gall bladder--> small intestine. Creates alkaline condition+emulifies. Best for enzymes.

Enzymes digest fat, protein&carbohydrates to make smaller molecules that can be absorbed.

Amylase:

-produced in small intestine, salivary glands, pancreas

-digests starch

-produces sugars

Protease:

-produced in stomach, pancreas, small intestine

-digests proteins

-produces amino acids

Lipase:

-produced in pancreas, small intestine

-digests lipids (fats&oils)

-produces fatty acids + glycerol

Biological detergents work better-used at lower temps-denature at hot temp. less electricity used

Biological detergents can have:

-protease enzymes to break down blood+food stains

-lipase enzymes to break down oil+grease stains

Industry:

-proteases --> baby food, predigest proteins // easy for baby to get amino acids to grow

-carbohydrases --> convert starch into sugar syrup // cheap sweetener

-isomerase --> glucose into fructose syrup // slimming product-- less needed

Advantages:

-work at low temps // less energy used

-fairly cheap

Disadvantages:

-expensive to produce

-supplied w/ food + o2

-costs to control pH level+temp

Isomerase converts the sugar glucose into fructose

Used to make soft centred chocolates // centre made of sucrose

Bacteria & yeast can be genetically engineered to produce ^ at industrial scales.

FERMENTATION

Enzymes kept at optimum temp&pH to make process efficient.

DOWNSTREAM PROCESSING

purification&filtration of the enzyme broth.