Enzymes (cont.2)
- Created by: Klmcgonigle
- Created on: 24-01-18 16:45
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- Enzymes
- Cofactor
- Prosthetic groups
- The enzyme carbonic anhydrase contains a ZINC ion as a prosthetic group
- a cofactor that is permanently bound (covalently) to an enzyme
- the presence of certain ions that may temporarily bind to enzyme or substrate may ease the formation of ES complexes and increase the rate of reaction
- co-substrates - they and the substrate together form the complementary shape to the active site
- Chloride ions are needed for amylase
- Coenzymes
- Are chemically changed during a reaction and need to be recycled to their original state
- Many are water-soluble vitamins
- Small organic non-protein molecules that bind temporarily to the active site
- a substance that has to be present to ensure that an enzyme catalysed reaction takes place at an appropriate rate
- Prosthetic groups
- Inhibitors
- Competitive inhibition
- The amount of inhibition depends on the relative concentration of substrate and inhibitor
- Increasing substrate concentration dilutes the effect of the inhibitor
- If the inhibitor binds irreversibly, it is an INACTIVATOR
- substances that have a similar shape to the substrate and so compete to bind with the active site
- form an enzyme-inhibitor complex that is catalytcally inactive
- The amount of inhibition depends on the relative concentration of substrate and inhibitor
- Non-competitive inhibition
- reduces the maximum (initial) rate of reaction
- the higher concentration of NCI's, the greater degree of inhibition because more enzymes are distorted
- molecule attaches to an allosteric site, disrupting the tertiary structure and changing the active site shape
- used in control of metabolic sequences
- A substance that reduces or stops an enzyme controlled reaction
- End product inhibition
- product molecules stay tightly bound to the enzyme to prevent the enzyme from forming more produc
- negative feedback regulation
- Competitive inhibition
- Metabolic poisons
- Cyanide
- inhibits aerobic respiration and catalase
- Snake venom
- inhibits an enzyme in neuromuscular synapses, which keeps the muscles contracted = paralysis, suffocation
- Cyanide
- Medicinal drugs
- Aspirin
- inhibits enzymes that lead to higher sensitivity to pain
- Protease inhibitors
- competitively inhibit viral protease enzymes to prevent viral coats from being
- Aspirin
- Cofactor
- (e) the need for coenzymes, cofactors and prosthetic groups in some enzyme-controlled reactions -To include Cl – as a cofactor for amylase, Zn2+ as a prosthetic group for carbonic anhydrase and vitamins as a source of coenzymes. (f) the effects of inhibitors on the rate of enzyme controlled reactions. To include competitive and non-competitive and reversible and non-reversible inhibitors with reference to the action of metabolic poisons and some medicinal drugs, and the role of product inhibition
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