Questions tagged [proteins]
For questions about proteins. Proteins are biopolymers consisting primarily of polycondensated amino acids.
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Testing whether an unknown powder is wheat gluten (at home)?
Last week, I ordered wheat gluten to make seitan. I received some powder and attempted a recipe, which mixes 100g of water with 100g of gluten to form a sticky dough. However in my case, I only got a ...
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How is it known that proteins are polymers of amino acids?
I read the following here.
In 1902, Emil Fischer and Frank Hofmeister independently proposed that proteins are formed from many amino acids, whereby bonds are formed between the amino group of one ...
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Strange Binding Curve DNA:Protein Interaction
So I did some DNA:Protein Interaction studies using Fluorescence Polarisation Assays. I have fluorescently labelled DNA and add my Protein of interest. Down below you see an exemplary plot of the ...
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Assessing stability of protein used for interaction experiments after changing buffer from tris to HEPES
I have a protein with a theoretical $\mathrm{pI}~9.0$ currently stored in $\pu{25 mM}$ tris and $\pu{250 mM}$ $\ce{NaCl}$ $(\mathrm{pH}~8)$ at $\pu{−80 °C}.$ I need to do experiments in HEPES at $\...
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What is the industrial alternative to dialysis?
I want to separate a recombinant protein from imidazole. Both of them are in a solution of pH 8. I was thinking of using ion exchange chromatography with cationite: the imidazole being positively ...
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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 ...
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Calculate IC50 from fluorescence kinetic
I have an assay in which a fluorescence signal is generated when the enzyme reaction progresses. The fluorescence signal increases until a maximum is reached. Than it keeps constant. The first 1 h ...
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What can I do if a peptide won't go in solution in a biological assay?
I have working on the realisation of on assay, that is intended to examine the activity of a protein. The assay works in a way, in which the product of the target enzyme is transfered by a support ...
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Troubleshooting an AutoDock Vina error on Chimera: “Could not find an atomic number for Hn Hn”
After minimizing a ligand (prepared with MarvinSketch) and preparing a target enzyme to dock said ligand onto (collected from RCSP PDB — 5DGN (Crystal structure of human FPPS in complex with compound ...
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When optimizing AMBER molecular dynamics parameters for protein-ligand interactions, how do I balance accuracy and efficiency?
Are there established practices for fine-tuning AMBER MD parameters in scenarios like mine, involving specific factors like mutant proteins or non-standard ligands? Has anyone successfully tackled ...
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Why don't proteins form branched polymers?
My reference book (Princeton Review for SAT Chemistry Subject Test) mentions that:
Proteins and carbohydrates are both polymers; however, only
carbohydrates commonly form branched polymers. Glycogen ...
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Non-toxic alternative to borax for use in slime chemistry?
I understand that sodium tetraborate decahydrate ($\ce{Na2B4O7•10H2O}$) and water is the primary binder for PVA glue based slimes.
We have learned borax is not good for the ground water, or marine ...
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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 ...
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Peptide bond formation involving side chains of charged amino acids
Peptide bonds are formed as such:
Aspartic acid, glutamic acid and lysine all contain either one extra $\ce{-COOH}$ or $\ce{-NH2}$ group in them. Why does that extra group not participate in peptide ...
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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. ...
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