All Questions
29
questions
2
votes
0
answers
25
views
Reason for differences in AChE aging/reactivation kinetics between neutral and charged organophosphorus inhibitors
According to the referenced papers, acetylcholinesterase that has been inhibited by an organophosphate possessing thiocholine as its leaving group is more susceptible to reactivation by oxime ...
- 1,264
3
votes
1
answer
105
views
Effect of presence of competitive inhibitor on observed reaction constant
Suppose there is a solution of enzyme, its substrate, a competitive inhibitor, and a suicide inhibitor. The reaction rate constant for the reaction of the suicide inhibitor with the enzyme is known. ...
- 1,264
3
votes
1
answer
174
views
Effect of competitive inhibitor on substrate inhibition
In an enzyme that undergoes substrate inhibition, how would the presence of a competitive inhibitor affect said substrate inhibition? Would the substrate concentration at which substrate inhibition ...
- 1,264
2
votes
0
answers
39
views
How are enzyme inhibition constants assayed for "multi-inhibitors"?
Suppose there is a suicide inhibitor of an enzyme that reacts with the enzyme to form an inactive enzyme and another product. This "Another product", however, is capable of acting as a ...
- 1,264
2
votes
1
answer
92
views
By what mechanism does amylase catalyze hydrolysis?
I've recently been learning bits and pieces of starch metabolism, and am wondering if anyone could explain exactly what is going on when alpha or beta amylase "cleaves" the 1-4 glycosidic ...
1
vote
0
answers
31
views
Why is AChE inhibited by triflates not susceptible to reactivation?
According to a report, certain esters of trifluoromethanesulfonic acid are capable of acting as irreversible inhibitors of acetylcholinesterase. Also, 3-PAM, while capable of reactivating AChE ...
- 1,264
1
vote
1
answer
822
views
How does one derive a KD from an equilibrium titration experiment? I am definitely making a mistake somewhere
Any help would be greatly appreciated. Thank you in advance.
If I have an antibody A and a target B, and experimentally titrate the antibody against a single concentration of B, and then measure the % ...
- 13
2
votes
2
answers
139
views
How do I obtain a 3D MOLFILE for the lactose synthase structure, especially the catalytic center?
So for example there is a paper by Ramakrishnan and Qasba which presents a model in a 3d stereo picture it has UDP-Gal, Glc, Mn++, a piece of the lactalbumin protein (?) and a piece of the lactose ...
- 381
1
vote
1
answer
52
views
Do phosphoryl thiocholines, their uncharged analogs, and other organophosphates, interact differently with Acetylcholinesterase?
As asked in the title, would the various salts -such as hydrochloride or methyl iodide- of V-Agents interact any differently with acetylcholinesterase compared to the neutral compound? For instance, ...
- 1,264
3
votes
1
answer
66
views
Differences in AChE inhibition kinetics between paraoxon and methyl paraoxon
According to literature, dimethyl paraoxon has a reaction rate constant for the aging (spontaneous dealkylation) of acetylcholinesterase of $\pu{0.186 h-1}$, a spontaneous reactivation rate constant ...
- 1,264
3
votes
0
answers
34
views
Differences in AChE inhibition kinetics between VX and VR
According to the referenced paper, VR has an AChE inhibition reaction rate constant almost 4 times that of VX. Interestingly, its reaction rate constant for aging of the enzyme is less than that of VX,...
- 1,264
2
votes
0
answers
132
views
How can DI water inhibit peroxidase activity?
I'm troubleshooting an IHC staining issue, and according to Thermo-Fischer's website, "Deionized water can sometimes contain peroxidase inhibitors that can significantly impair enzyme activity.&...
2
votes
0
answers
37
views
Why is Chlormephos highly toxic despite requiring metabolic activation?
According to the book "The Chemistry of Organophosphorus Pesticides", the insecticide Chlormephos (S-(chloromethyl) O,O-diethyl phosphorodithioate) has an oral LD50 in rats of 7 mg/kg. For ...
- 1,264
4
votes
1
answer
167
views
Why are isomers of parathion less active acetylcholinesterase inhibitors than paraoxon?
Parathion itself has been found to be a very weak inhibitor of acetylcholinesterase. It normally requires metabolic activation and the conversion into paraoxon in the body to actually start exhibiting ...
- 1,264
0
votes
0
answers
123
views
What is the chemical reaction behind ginger milk curd?
Pouring hot milk into ginger juice solidifies the milk. All I know is that ginger juice contains Zingibain that could break down milk proteins into smaller polypeptides. I'm confused as though why is ...
- 121