Enzymes Flashcards
(18 cards)
Metabolism
The sum of all chemical reactions in the body.
Enzymes
Folded, globular shaped protein catalysts that speed up chemical reactions.
Catabolic enzymes
Enzymes that break down big molecules into smaller ones.
-Amylase is an enzyme present in saliva and in pancreatic juice that catalyses the break down of starch (polysaccharide) into maltose (disaccharide).
Anabolic enzymes
Enzymes that build up large molecules from smaller ones.
The lock and key model
Enzymes have a rigid shape.
The induced fit model
The active site is flexible.
Active site
The active site of an enzyme is the area where the substrate enters and is changed into a product(s).
Specificity
Refers to an enzyme’s ability to react with only one substrate.
Factors affecting enzyme action:
-pH
-Temperature
Optimum activity
The optimum activity of an enzyme is the condition(s) under which an enzyme works best.
Denatured enzymes
Is an enzyme that has lost its function due to a change in its shape.
Bioprocessing
The use of living cells or their components, such as enzymes, to make useful products or to carry out useful functions.
-Eg. The use of yeast and sugar to produce beer. Yeast cells respire anaerobically to produce alcohol.
Immobilised enzymes
Are enzymes that are attached to or trapped in an inert (inactive) insoluble material.
-Eg. Immobilised rennin is used to coagulate the proteins present in milk in the cheese making process.
-Advantages - Gentle, no contamination, reusable, stable.
Carrier-binding
Attaching enzymes to a water-insoluble substance, such as cellulose or agarose.
- Physical absorption, ionic binding and covalent bonding.
Cross-linking
Binds the enzymes together covalently.
Entrapment
Trapping the enzyme in a gel or a membrane.
Bioreactor
Is a vessel in which a product is formed by cells or a component, such an enzyme, eg, yoghurt.
-Feeding pump, submerged aerator, sensors probes, agitation system.
Batch cultures
Individual cycles
Continuous-flow cultures
Continuous cycles
