Lecture 3 - Biology 2A03 L3 Lecture 3 Protein Activity...

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Biology 2A03 – L3 Lecture 3 – Protein Activity Protein Activity 1. Proteins and protein function central to physiology 2. Protein activity is controlled by: 1. Rates of synthesis and/or degredation 1. Mutations, gene expression and decrease in cell metabolism affect rates of synthesis presence of transcription factors and protein inhibitors 2. Changes in 3D conformation (shape) (determined by amino acid composition) 1. Important for ligand binding to active binding site 2. Temperature changes protein shape as temperatures affect the weak bonds holding proteins together The shape of proteins and therefore ligand binding is modified by: 1. Allosteric Modulation 1. Non-covalent binding of factors to their regulatory sites results on a change in shape of the active site 2. E.g. substrate for fat synthesis inhibits enzyme in fat oxidation; motochindria to consume fat enzyme on mitochondrial membrane effective for consuming fat; substrate for fat synthesis inhibits this enzyme in fat oxidation (negative feedback system) 1. Covalent Modulation 1. Covalent binding of negative PO 4 2- to amino acid side chains (e.g. serine, theorine, tyrosine) by protein kinases 2. Changes protein conformation and distribution of negative charges 1
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This note was uploaded on 03/26/2011 for the course BIOLOGY 2a03 taught by Professor Nurse during the Spring '10 term at McMaster University.

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Lecture 3 - Biology 2A03 L3 Lecture 3 Protein Activity...

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