PM1B Revision - James Hall and Sarah Allman by James Hall https://padlet.com/dr_james_hall/z3mwp20fw20z en-us 2019-04-26 09:24:48 UTC 2026-01-29 15:35:29 UTC hello@padlet.com Dr_James_Hall https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354388884 Please feel free to post any questions here!]]> 2019-04-26 09:32:12 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354388884 https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354510273 We'll check this Mondays, Wednesdays and Fridays]]> 2019-04-26 16:09:39 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354510273 https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354719530 In the structure and function lectures it mentioned that in non competitive inhibition, substrate inhibition isn’t affected. Why is that so? When normally we learn that when an inhibitor binds on the enzyme elsewhere it changes the active site shape? 

Thank you ]]> 2019-04-28 00:03:16 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354719530 Dr_James_Hall https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354955921  
Hi 

I am assuming that you meant to say that the “substrate binding” (rather than “substrate inhibition” isn’t affected? 
If so then this is correct – the binding of the substrate is not affected by a non-competitive inhibitor. The inhibitor doesn’t change the overall shape of the enzyme and therefore the substrate can still bind. However, the inhibitor could work in a couple of different ways to prevent the enzymatic reaction from taking place. For example, the inhibitor could prevent the enzyme from undergoing a conformational change that is necessary for the reaction to occur. This doesn’t stop the substrate from binding but it would block the reaction. Hope this helps! 

James 

]]> 2019-04-29 11:32:42 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/354955921 https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/356835621 With regard to drug binding interactions at enzyme active sites, how can you differentiate between electrostatic interactions and dipole-dipole interactions - they both are important for initial binding, occur over long distances and both involve opposite charges attracting - Help please]]> 2019-05-04 15:15:22 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/356835621 Dr_James_Hall https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358855036 Hi there. I think you might be a little confused between ion-dipole and dipole-dipole interactions. The latter are weak interactions (compared to electrostatic or ion-dipole). If you look at slide 22 of lecture 1 you can see how the distance dependence changes for each interaction. For electrostatic interactions, if you double the distance you get half the intensity. For ion-dipole, if you double the distance you get a quarter of the intensity and for dipole-dipole, if you double the distance you divide the intensity by 8. ]]> 2019-05-10 13:03:14 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358855036 Dr_James_Hall https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358856100 However one easy way to differentiate between electrostatic, ion-dipole and Van der Waals interactions is to look at the number and type of charges involved. For an electrostatic interaction you must have a positive charged group interacting with a negatively charged one. These must possess formal positive and negative charges. For ion-dipole, only one group needs a formal positive or negative charge, the other must possess a dipole. For dipole-dipole interactions, neither group will possess a full formal positive or negative charge.  

]]> 2019-05-10 13:05:49 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358856100 Dr_James_Hall https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358856965 In any molecule, electrostatic interactions are those which are felt over the longest distance and are the most important for guiding the molecule to its target. However, this assumes that the molecule AND the active site have groups which have a positive or negative charge, which doesnt apply to all molecules or proteins. The second option is the ion-dipole, which is still felt over some distance but not as far as an electrostatic interaction. If the drug/target cannot support an electrostatic interaction then it is the ion-dipole interaction which drives that attraction.

]]> 2019-05-10 13:07:54 UTC https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358856965 Dr_James_Hall https://padlet.com/dr_james_hall/z3mwp20fw20z/wish/358857246 In summary, both can drive the interaction but the electrostatic interaction is the strongest and most important IF the target and molecule can interact in that way

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