Questions tagged [biochemistry]

This tag is for questions concerning biochemical methods (e.g. electrophoresis) or those concerning biochemical mechanisms or research. Do not use this tag if your question is merely about compounds often used in areas related to biochemistry or associated with these. These may fall under organic chemistry or the appropriate compound’s functional groups’ tags.

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6
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1answer
525 views

Can I damage a biotinylated antibody in solution by vortexing or mixing too vigorously?

I am running an immunoassay using biotinylated antibodies and have noticed a decreasing trend from duplicate assay runs (completed within minutes of eachother) from the same vial. In between each ...
4
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2answers
620 views

Can luciferin + ATP → luciferyl adenylate + PPi be reversed?

Reading about the light emitting reaction of luciferin + ATP, catalysed by luciferase I am confused about the following. On this webpage the partial formula is written as: luciferin + ATP → ...
2
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1answer
2k views

Synthetic roadmap from 3-methyl-2-butanol to 2-methyl-2-butanol

This is for a homework assignment, I'm usually very good with reactions and am really disappointed after getting it wrong four times, where did I go wrong?
2
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1answer
2k views

Photosynthetic rate calculation

What are the steps in calculating the photosynthetic rate ($\mu\text{mole}\ce{O2}/$ $\text{m}^2 / \text{min}$) for a leaf that has an area of $0.0025 \text{m}^2$ and a $\ce{O2}$ evolution rate of $...
2
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0answers
216 views

Can TBE electrophoresis buffer be stored in a PETE container?

I'm doing a science project on agarose gel electrophoresis and would like to know if it is safe to store Tris/Borate/EDTA buffer solution inside a PETE container since I will be making about 10L of ...
11
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3answers
246 views

Would it be possible to produce a non-toxic atmosphere using a coal fire and frozen oxygen?

A Pail of Air is a classic science fiction short story by Fritz Leiber from 1951 describing how a family survives on an Earth that has left its orbit around the sun, using desparate low-tech methods: ...
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2answers
79 views

Explaining the reaction

i am an immunology master student without prior knowledge of biochemistry. Could someone explain me this 6 reactions ? I could learn the reactions by heart. But i want to understand, why exactly the ...
2
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1answer
76 views

What is the scaling for % completion time in a Michaelis–Menten scenario as a function of substrate concentration?

Say I have a straightforward Michaelis-Menten reaction where an enzyme $E$ at some fixed concentration $[E]$ forms an interaction complex $ES$ with a substrate $S$ (with initial concentration $[S]_0$),...
11
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1answer
1k views

What molecular features create the sensation of sweetness?

There are many compounds that taste sweet. Many of the artificial ones taste much sweeter than natural sugars (which is why they contribute little to energy intake when use as sweeteners). A range ...
15
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3answers
1k views

What is the mechanism of action of anaesthetics?

A range of very different compounds are used in medicine as anaesthetics. They don't seem to have much in common chemically but they all seem to keep people asleep while medics are doing nasty things ...
5
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1answer
105 views

How to estimate reaction products of competitive binding?

I have two reactions, $$\ce{A + C \rightleftharpoons AC}$$ $$\ce{B + C \rightleftharpoons BC}$$ I'd like to estimate the relative steady state proportions $$\frac{[\ce{BC}]_{SS}}{[\ce{AC}]_{SS}+[\...
2
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1answer
294 views

Does using stonger soaps help me lose weight?

Soaps are amphiphilic molecules that, practically, removes body oils from the surface of the skin. The body, on the other hand, always replenishes sebum through the sebaceous glands after a certain ...
3
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2answers
459 views

Is aromaticity of the 4 aromatic amino acids affected by pH?

During a discussion of NMR, my lecturer told me to think about which amino acids contain protons in an aromatic ring, and whether any are likely to be affected by changes in pH. The 4 aromatic amino ...
11
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2answers
10k views

At what amount is digesting soap unhealthy?

Several of my friends, when they do the dishes manually, do not rinse the dishes after cleaning but merely dip them in the dishwater and then dry them (using a towel or a dish rack). I myself on the ...
2
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1answer
258 views

Coupled and Coupling Reactions

Is Coupling Reactions, Heck Reaction for example, different from Coupled Reactions like the production of Glucose 6-phosphate in living organism?
4
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2answers
1k views

How do I remove free biotin after biotin-protein conjugation?

I want to quantify a biotin-protein conjugate after chemical biotinylation. After biotinylation, the solution contains both biotinylated protein and free biotin. I intend to use a HABA-avidin biotin ...
8
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1answer
321 views

When and how in anaerobic digestion is water dissociated?

Anaerobic digestion and methanisation of organic feedstocks is a complex series of processes that result in biogas. One way to look at this is a very top-down, stochiometric approach as in the Buswell ...
3
votes
1answer
141 views

Isoelectric pH of colloids?

How did we derive the relation between the isoelectric pH and the dissociation constants for the amino and carboxyl groups on zwitterionic amino acids. $$pI=\frac {pK_{a1}+pK_{a2}}{2}$$ where $$\ce{...
1
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1answer
644 views

Epimerization in peptide synthesis

How can epimerization during peptide synthesis be detected? And how can we change or modify the coupling conditions to stop epimerization occurring?
10
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2answers
377 views

How can enzyme/substrate reactions that adhere (largely) to quantum theory also require 'Newtonian' consideration of gravity?

I'd just like to ask for a little clarification here due to confusion from interdisciplinary studies. I'm currently reading the 1976 paper related to the recent 2013 Nobel Prize for Chemistry, by 2 ...
1
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0answers
80 views

An alternative to dimethylsulfoxide (DMSO) for cryoprotection?

Is there an appropriate alternative to DMSO? I mean for embryo or oocyte freezing? I am a PhD student at present. I am going to study this substance and I'm very interested in this field.
1
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1answer
287 views

Thermodynamic vs. Kinetic products

With regards to complexes, I read that thermodynamic products are favored over kinetic products, which are labile. Why wouldn't the first product formed be the most prominent?
7
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1answer
96 views

Does it make a difference in energy if a reaction is done in many steps or in one step?

I am particularly interested in knowing about glucose breakdown. If we artificially burn glucose, will the energy released be the same if it is broken down in steps(like in a living cell)?
10
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1answer
534 views

Is there a difference between imidazolidinone and imidazolidone?

I've had my nose in the early literature on GFP (Green Fluorescent Protein), which contains a 4-(p-hydroxybenzylidene)imidazolidin-5-one fluorophore, and in one paper the author refers to the "...
1
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2answers
40 views

Are phosphomonoesterases solid?

What state of matter are phosphomonoesterases? I am not a biochemist; while I've found various lists of such enzymes, and plenty of (to me) barely comprehensible articles describing their production, ...
4
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1answer
2k views

Dead-body Ashes: biodegradable or not?

In many cultures, human dead bodies are burnt to ashes, which is then thrown in rivers and some time buried in earth. Are human ashes after burning dead bodies biodegradable? Note: Earlier I posted ...
4
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1answer
270 views

What does an endpoint saturated signal mean. How does it relate to equilibrium constant?

I have had a question that has been bugging me for a couple of years in my graduate school career, and I was wondering if perhaps someone could help explain it to me. Given an endpoint assay like this ...
24
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1answer
246 views

When measuring avidity should you use the ligand concentration or the nanoparticle concentration?

Looking at avidity between a ligand-receptor, you're looking at an enhancement of the $K_d$ compared to a lone ligand. Is it more appropriate to compare the $K_d$ using the concentration of the "...
6
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3answers
3k views

How can I measure the pH of high-viscosity fluids like dough?

I would like to measure the pH value of dough with a pH-Meter, to ensure a pH value of 4.1 (max). Because of the high viscosity I would thin down the dough with demineralized water for two reasons: I ...
7
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1answer
161 views

Interpretation of Figure - biofunctionalization

In this paper on page 1985 they say: Fluorescence analysis confirmed that enhanced protein binding at higher electron dose depends only to a small extent on the slight increase in the lateral ...
18
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1answer
8k views

Why are the halogens good disinfectants?

I've been searching around the internet for a while and I know that Chlorine, Bromine and Iodine are used as disinfectants. My question is, what is the property of the halogens that make them ...
2
votes
1answer
4k views

Assay over 100% (L-Cysteine Hydrochloride Monohydrate)

In reading a COA (Certificate of Analysis), I came across an Assay line: The Assay is 100.5% where "Lower Limit" is 98.5 and "Upper Limit" is 101.0 This product ...
6
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2answers
6k views

How can potassium disappear after cooking?

I read this at this webpage: http://www.whfoods.com/genpage.php?dbid=90&tname=nutrient#impactcookingstorageprocessing How do cooking, storage, or processing affect potassium? Potassium ...
8
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1answer
8k views

Why does heat solidify cake batter?

Increased vibration causes the atoms in an object to spread out farther away. Thus, with added heat, and object goes form a solid to a liquid to a gas (and then to plasma, with enough heat). Why is it ...
2
votes
1answer
182 views

Do proteins bind to carbon? If so how?

Can someone explain me whether a protein (like an antibody) would bind to carbon? The carbon arises due to electron beam induced deposition of Polyethylglycol (PEG). The carbon molecules that arise ...
2
votes
1answer
168 views

PEG (polyethylene glycol) and ITO (indium tin oxide)

The binding of proteins to an ITO surface can be prevented by coating it with PEG groups (polyethylene glycol). PEG-silane is used to create the coating. can somebody help with: Why does PEG-silane ...
5
votes
2answers
37k views

How do we assign alpha/beta status in polysaccharides?

In polysachharides like sucrose or any other disachhaharides, how is it that we assign whether the glycosidic bond is alpha/beta ? For example the images here: http://forums.studentdoctor.net/...
0
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1answer
101 views

Plastic: Reputable Publications

I would just like some reputable textbooks and or publication companies that have extensive research on plastics, as, for example, dealing with life cycles of plastics, degradation factors, effect on ...
3
votes
1answer
308 views

Michaelis Menten derivation for 2 enzyme substrates

We know the Michaelis Menten derivation for the following reaction: $$\ce{E + S <=> ES -> E + P}$$ However, what if the reaction took place in a different scenario whereby: $$\ce{E + S <...
3
votes
1answer
267 views

Best way to dissolve and consume cysteine HCl monohydrate powder

Does cysteine break down in filtered water? Should this made more acidic? If I mix cysteine powder in juice (something acidic maybe), does it remain at cysteine? It seems that it can oxidize into ...
1
vote
1answer
551 views

Why do we need to incubate this system for 18 hours at 60 degrees Celsius?

I am conducting a bio-chemistry related experiment and I have been unable to understand a step which is commonly performed. The procedure that is confusing me is outlined in the supporting information,...
2
votes
1answer
185 views

Does tolerance to alcohol affect blood/breath alcohol levels?

When blood / breath alcohol levels are taken to determine how intoxicated a person is, does it depend on their tolerance ? i.e. If you had two people of identical age, weight, fitness, etc. person A,...
16
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2answers
837 views

Why do chalcogens (Group VI) stink so badly?

For more fun with Dr. Derek Lowe, see this for a primer: Things I Won't Work With - Carbon Diselenide. The short of it is that we carbon-based life forms generally like oxygen. However, move just one ...
3
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3answers
9k views

Homemade preservative for natural aloe-vera gel?

I suppose this question can be extrapolated to food in general, but it is the case that I would like to know if there are any methods that would help me to keep the aloe gel fresh, i.e. avoiding it to ...
3
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2answers
951 views

Recreational drugs by half life

I am interested in the Biological Half Life of substances. In the previous wikipedia link, I've already found the half lives of common pharmaceutical products. I can't seem to find similar data for ...
1
vote
1answer
187 views

What metabolite intermediate will accumulate in a mammalian cell-free extracts capable of glycolysis if lactate dehydrogenase is inhibited?

I know the reaction proceeds as follows: Pyruvate accepts the electrons from NADH to form lactate. What would be the intermediate in this reaction? Would it be NADH or NAD+?
6
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1answer
1k views

Is it possible to separate salt from food, or at least convert it into something that doesn't taste salty?

A couple months ago, one of my room mates accidentally used a cup of salt to make apple crumble. She asked if there was any way to separate it, probably because I had recently reduced the acidity of a ...
5
votes
1answer
173 views

What are the factors controlling the fate of post-adhesed volatile molecules of the olfactory epithelium?

What happens to volatile molecules that reach the main olfactory epithelium in the nasal cavity after they bind and the neural stimulus fades? To what extent do such factors as receptor kinetics and ...
2
votes
1answer
47 views

Which mutated enzymes act as better drugs than their non-mutated form?

Is there an enzyme which is used as a drug (let it be called version $A$) and a mutated version of it ($M$), where the activity of $M$ was found to be higher than $A$? Any references on such a case ...
3
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2answers
3k views

How can I control the oxygen in an erlenmeyer flask in a bioprocess?

I need to control oxygen in a erlenmeyer flask in a bioprocess. I need to remove overall oxygen in a erlenmeyer flask, and after I need to add oxygen in controlled amounts to a culture in a shaken ...