Enzymes Flashcards
enzymes are
biological catalysts
advantages of enzymes as inorganic catalysts
specific to 1 catalytic reaction, don’t produce a range of unwanted byproducts, a lot faster
extracellular enzymes
some enzymes are secreted from the cells where they’re made and act on their substrates extracellularly
why are enzymes specific in their action
each have a specifically shaped active site that is complementary only to the shape of the substrate molecule
why are enzymes described as biological catalysts
speed up reactions by up to 10^12 times at lower temperatures, neutral pH and normal pressures
able to function in conditions that sustain life
unchanged and reusable at end of reaction
turnover number of an enzyme
the number of moles of substrate converted to product per mole of enzyme per second under conditions at which the concentration of all substrates is saturating
why a non-functioning enzyme may cause serious disease
a metabolic disease due to genetic mutations which don’t allow the enzyme to catalyse chemical functions in the body to work normally
activation energy
chemicals need energy to activate reaction in order to increase kinetic energy of the molecules so they move more and are likely to collide then reaction more successfully- enzymes lower this to speed up metabolic reactions
Cofactor
Any substance that must be present to ensure enzyme-controlled reactions take place at the appropriate rate- non-protein
Coenzymes
Small, organic, non-protein molecules
Prosthetic groups
A cofactor permanently bound to an enzyme
Enzyme inhibitor
Any substance or molecule that slows down the rate of an enzyme controlled reaction by affecting the molecule in some way
Multi-enzyme complexes
Increase efficiency of metabolic reactions without increasing substrate concentration as they keep the enzyme and substrate molecules within the same vicinity and reduce diffusion time
Why are many metabolic reactions carried out in particular regions or organelles
Increases efficiency of metabolism and some of the enzymes within organelles are bound into the organelle membrane
Allosteric site
Region of an enzyme away from the active site where a non-competitive inhibitor may attach
Inactivators
When permanent inhibitors denature the enzyme they are called
Medical drugs that act by enzyme inhibition
Aspirin, ATPase inhibitors, ACE inhibitors, protease inhibitors, nucleoside reverse transcript inhibitors
Active site
Indebted area on the surface of an enzyme molecule with a shape that is complementary to the shape of the substrate molecule
Catalyst
Chemical that speeds up the rate of a reaction and remains unchanged and reusable at the end of a reaction
Metabolic/metabolism
The chemical reactions that take place inside living cells or organisms
Product
Molecule produced from substrate molecules by an enzyme-catalysed reaction
Substrate
Molecule that is altered by an enzyme-catalysed reaction
Enzyme-substrate complex
Complex formed by temporary binding of enzyme and substrate molecules during an enzyme-catalysed reaction
Enzyme-product complex
Enzyme molecule with product molecules in its active site joined temporarily by non-covalent forces
Q10
Temperature coefficient calculated by dividing the rate of reaction at (T+10)’C by the rate at T’C
Concentration
Number of molecules per unit volume
Competitive inhibition
Inhibition of an enzyme where the inhibitor molecule has a similar shape to the substrate and competes with it for the enzymes active site preventing formation of ES complexes
Inhibitor
A substance that reduces or stops a reaction
Non-competitive inhibition
Inhibition of an enzyme where the competitor molecule attached to a part of the enzyme but not the active site, if changes the shape of the active site which prevents ES complexes forming as it’s no longer complementary in shape
3 ways inorganic ion cofactors increased the rate of enzyme-catalysed reactions
certain ions, co-substrates, changing charge distribution
