BIOSC 150 1nd Edition Lecture 28Outline of Last Lecture I. Study of EnzymesOutline of Current Lecture 1. Study of Enzymes 2. Helpers3. Regulators4. Reaction RateCurrent Lecture“Helpers”- Non-protein helpers help enzymes to function o These helpers are derived from vitaminso Vitamins synthesize coenzymes- Helpers aid in the transfer of electrons, carrying something to the reaction- Helpers are not part of the enzyme – they simply react then leave- Examples: Nad, Coenzyme A, FADo Reaction rate depends on substrate concentrationo At V-max enzyme is saturatedo There are no more available binding sites for the substrate therefore the reactionlevels off (plateaus) when there is a high level of substrate (saturated reaction)o Reaction rate depends on temperatureo Going up, there is an increase in kinetic energy in order to reach the transition state of the reactiono Going down, denaturing of the protein is taking place – due to increased vibration/ twisting and disruption of bonds in side chainThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o There is an optimal temperature for each reaction based on composure of the enzyme and its side chainso Reaction rate depends on pHo Hot environments have an optimal pH of 3o Cold environments have an optimal pH of 7o Charge of side chain changes with the pH and can affect binding to the active site(pH affects amino acid charge)o There are more protons at low pH therefore protonation of the side chain is more likely to occurProtease- mediated cleavage can regulate enzyme activity (irreversible reaction)o Phosphorylation can regulate enzyme activity by affecting the conformational change and therefore allowing substrates to get in and bind (activating the protein) o Reversible reactionAllosteric Regulators- important in the metabolism o Bind to site other than the active siteo Bound: favors substrate bindingo Unbound: unfavorable, inhibits substrate
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