BCH 2333 Lecture 11: Protein Function
21 Mar 2016
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Protein binding & allostery - chapter 7, 8. 8. Proteins that bind ligand and do chemistry = enzyme. Molecular recogniion - one molecule can recognize another through weak bonding interacions. General binding described by the dissociaion constant kd. Kd = [p][l]/[p-l] gives the eq constant for breakdown of product. o. Protein bound with ligand (p-l complex: dissociaing protein bound to ligand o o o. S = substrate, i = inhibitor; also called pi or ps complex. E = enzyme so can be el, ei, or es complex. Kd = [p]{l}/[p-l], gives an eq constant for break down of product: meaning of kd . 1 kd = concentraion so units are mol/l. Ka = 1/m, less obvious as to what this means. Kd gives the concentraion of a ligand that saturates 50% of the sites. [p]=[p-l] at 50 % bound so [p]/[p-l]= 1. Almost all binding sites are saturated if the ligand concentraion is 10 x kd.
