Chapter 9 & 10: Enzymes

Enzyme

biolgical catalyst made of protetin, highly folder 3D shape

Catalyst

substcance that speeds up a reaction without being used up

Substrate

substance on which an enzyme reacts

Product

substances the enzyme forms

Active Sites

areas along the surface of an enzyme that allows substrates to attach

Enzyme Reactions

reversible, which means they can be anabolic and catabolic

Anabolic

building up complex substances

Examples of Anabolic Enzymes

DNA ligase, DNA polymerase

DNA Ligase

used in genetic engineering to join two pieces of DNA together

DNA Polymerase

an enzyme that repairs and forms DNA

Catabolic

breaking down of complex substances

Examples of Catabolic Enzymes

amylase, catalase

Amylase

converts starch into maltose, allows seed germination

Catalase

converts hydrogen peroxide into water and oxygen

Factors Affecting Enzyme Activity

pH, temperature

pH In Relation to Enzymes

enzyme shape changes when pH changes, if pH is too low or high the enzyme changes shape

Temperature

at low temperatures enzyme activity is reduced, increase in temperature increases enzyme activity however above a certain temperature enzymes change their 3D shape

Denaturing Enzymes

active sites are destroyed when denaturing occurs which means substrates cannot attach and enzyme cannot function, cannot be reversed

Immobilised Enzymes

enzymes that are attached or fixed to each other or to an inert material

Bioprocessing

use of enzyme-controlled reactions to produce a product

Bioreactor

vessel or container in which living cells or their products are used to make a product

Methods of Immobilising Enzymes

attaching them to one another, adsorption, enclosing in a membrane or gel

Adsorption

enzymes physically attached to inert supports

Enclosed in Gel

allows entry of substrate and exit of products, but does not allow enzyme to leave

Advantages of Immobilised Enzymes

lower costs, product does not need to be separated, increased enzyme stability

Uses of Immobilised Enzymes

fructose from glucose and isomerase, antibiotics from penicillin and penicillin acylase

Induced Fit Model

substrate combines with the 3D active site of the enzyme, active site is induced to change shape slightly by the substrate, substrate and enzyme form an enzyme-substrate complex, bonds in the substrate are altered to change into the products

Enzyme Specificity

each enzyme will react with only one particular substrate

Optimum pH

pH value at which an enzyme works best

ADP

adenosine diphosphate, made of the base adenine, a five-carbon sugar called ribose and two phosphate groups, bond between the two phosphate groups is unstable.

ATP

adenosine triphosphate, forms when another phosphate group is added to ADP, energy is added in the form of the unstable bond between the last phosphate groups

Phosphorylation

process of adding a phosphate group

NADP+

nicotinamide adenine dinucleotide phosphate, low-energy molecule, involved in photosynthesis, can accept a pair of high energy elections to form NADPH

NADPH

electron and hydrogen carrier, energy and hydrogen it contains is used in photosynthesis to form glucose

NAD+

used in respiration as an equivalent low energy molecure to
NADP+

NADH

used as an equivalent high energy molecule to NADPH