BIOLOGY 2B03 Lecture 2: Regulation of Function (Module 2)
30 Nov 2016
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Properties that determine affinity & specificity of protein-substrate interactions. Enzyme kinetics & identify ways of calculating affinity. Proteins are capable of binding to every type of molecule including other proteins, small ions, metabolites, nucleic acids & carbohydrates. Examples (of protein binding): antibodies binding to target molecules (i. e. antigens); enzymes binding to substrates; dna-binding proteins associating with. Dna; receptors on surface of cell binding to signalling molecules (like growth hormone) Specificity: ability of a protein to preferentially bind to one/small number of molecules. Strong interaction one in which protein & its ligand are associated for long time. High affinity: strength of binding between protein & ligand. Both specificity & high affinity are dependent on molecular complementarity between ligand & surface of ligand binding site. Thermal motion rapidly breaks ill-fitted molecules (who form few non-covalent interactions) apart. Accumulation of non-covalent interactions allows molecules to stay together despite thermal motion.
