Proteins + Enzymes Flashcards
Activation energy
The required energy to enable a reaction to occur.
Active site
Area on an enzyme molecule to which substrate binds to.
Alpha helix
Protein secondary structure- coiling of polypeptide chain to form right-handed spiral held in place by Hydrogen bonds between C=O and NH groups.
Amino acids
Monomer of polypeptide, contains amine group (-NH2) and a carboxyl group (-COOH).
Amphotenic
Molecule which can act as acid and base.
Beta pleated sheet
Folded protein secondary structure held by H-bonds.
Biuret test
Biochemical test for presence of proteins.
Buffer
Substance which resists a change in pH when acid/ alkali is added.
Catalyst
Substance that increases rate of reaction but doesn’t take part in reaction, so is reusable.
Coenzyme
Organic non-protein molecules which bind temporarily with the substrate to an enzyme active site, essential for enzyme activity.
Cofactor
Molecule or ion helping enzyme work.
Competitive Inhibitor
Substance which reduces rate of enzyme-controlled reaction by binding to enzyme active site.
Condensation
Type of chemical reaction in which 2 molecules are joined together by covalent bonds forming larger molecules and releases water.
Denaturation
Irreversable change to tertiary structre of protein molecule, leads to loss of function in most proteins.
Disulphide bridge
Covalent bond formed between sulphur atoms in 2 cytosine and amino acid residues.
End product inhibition
Regulation of metabolic pathways where last product in sequence of enzyme-controlled reaction becomes the inhibitor of 1 enzyme earlier in sequence.
Enzyme
Biological catalyst speeds up metabolic reactions inside cells.
Enzyme substrate complex
Intermediate structure formed when substrate molecule binds to enzyme active site.
Fibrous protein
Protein with relatively long, thin structure, which is insoluble in water and metabolically inactive. Often has structural role within organism.
Globular protein
Proteins with relatively spherical molecules, soluble in water, often have metabolic role in organisms.
Hydrogen bonds
Weak electrostatic attraction between partially positively and negatively charged toms in polar molecules.
Hydrolysis
Reaction where large molecules are broken into 2 smaller ones by addition of water and breaking of covalent bond.
Induced-fit hypothesis
Theory of enzyme action where enzyme molecule changes shape to fit substrate molecule more closely as it binds to it.
Inhibition
Slowing of enzyme-controlled reaction using substrate which slows/prevents formation of enzyme-substrate complex.
