The scientific study of chemical processes in living organisms, including, but not limited to, living matter.

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How is Humic substance destroyed in nature?

Humic substance consists of many, to my knowledge poorly understood, species of organic matter, mostly carbohydrates chained in intersting (and also poorly understood) ways. Humic substance is an ...
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11 views

Does Bioglass 45S5 attach to enamel?

When I search, I see bioglass binds to bone and dentin, but nothing is said about enamel. The bioglass allows the creation of a hydroxyapatite, and from what I've read I think enamel is ...
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20 views

Concentrations of dNTPs

DNA Polymerase III has a Km of 10 micro moles for each of its four substrates (dATP, dCTP, dTTP and dGTP, or dNTCPs for short). During replication, Poll III adds, on average, 750 dNTCPs/sec to each ...
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34 views

Is photosynthesis endothermic and exothermic at the same time? … somehow?

Photosynthesis is obviously an endothermic reaction, I mean, what would be the point otherwise, right? This is probably just sheer and utter stupidity on my behalf, but why does Wikipedia say the heat ...
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38 views

Test for glyphosate in water, boolean style

Testing for contamination of the ever so popular glyphosate based herbicide "Roundup" in water is a service that many labs provide, one of them is the Microbe Inotec Laboratory . They use an enzyme to ...
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77 views

pH of amino acid solutions

Hi may someone help me with this question A glycine ($\ce{NH2CH2COOH}$) is a standard amino acid with two $\text{p}K_{a}$ ($\text{p}K_{1}=2.0$ for $\ce{-COOH}$ and $\text{p}K_{2}=10.0$ for ...
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58 views

Ratio of conjugate bases of a tricarboxylic acid

Hi does anyone know how to solve this question? A tricarboxylic acid $\ce{H3A}$ has three different types of $\text{p}K_\text{a}$ $(\text{p}K_\text{a, 1} =2.0,$ $\text{p}K_\text{a, 2}=5.0,$ ...
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59 views

Deriving goldman equation

So I've been trying to follow the derivation of the Goldman-Hodgkin-Katz equation on Wikipedia (https://en.wikipedia.org/w/index.php?title=Goldman_equation ) - I can follow it through after it sets up ...
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63 views

Which branches of chemistry and in what order to learn (self study)?

Hi I have decided to give chemistry another shot (it didn't take so well way back in high school). My main interest is for reading up on brain chemistry and pharmacology. I currently have a textbook ...
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35 views

A Material that sticks to the skin, without adhesives!

I am onto a project for making knee braces for female anatomy, and I have been looking for a material, that i could line the pads with, that would stick to the skin of the players and still provide ...
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33 views

Concentration from Absorbance vs Time

I am given a protein, BAPNA, and the initial concentration of the protein. The experiment involves reaction rates of varying protein concentrations. Each sample cuvette is inserted into a ...
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Does water really 'go bad' after a couple of days?

Among my friends it is a sort of 'common wisdom' that you should throw away water after a couple of days if it was taken from the tap and stored in a bottle outside the fridge, because it has 'gone ...
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36 views

What is “stuffy”/“stale” air composed of?

When a room is not ventilated for a long time (days if people are present, weeks if not), humans perceive a change in air quality commonly described as "stale" or "stuffy" air. What is going on here ...
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60 views

Products of the o-Toluidine oxidation with glucose oxidase and peroxidase

Could anybody describe which product is formed in the following reaction (o-Toluidine oxidation)? $$\ce{H2O2 + o-Toluidine_{uncolored} - Peroxidase -> H2O + 1/2 O2 + o-Toluidine\; ...
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170 views

Gold's atomic structure and bonding in relation to the separation techniques used

How is Gold's atomic structure and bonding related to the separation techniques used to distinguish it from other substances? I'm just confused on what I'm actually searching for, I have read so ...
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49 views

Biochemistry for a mathematics student?

I am a second year mathematics student. I am mostly interested in statistics. Right now my curriculum doesn't offer me much choice (all second year courses are mandatory) but next semester I will be ...
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80 views

Spectrophotometric assay by pNPP

Here is a series of related questions that I want to ask. If you think they ought to be different questions, please tell me so. Background The activity of acid phosphatase is measured by an ...
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47 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 ...
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69 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 → ...
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38 views

Using Spectrophotometer to analyse enzyme reaction

Suppose we have two enzymes with concentration of 1X and 0.1X We then add a substrate and incubate the mixture for 1 or 10 or 20 minutes.( So,there will be total of six samples.) Question ...
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104 views

Help with synthesis flowchart, please

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?
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30 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 ...
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105 views

Peptide sequencing problem:

A nonapeptide was divided into three samples and each sample was subjected to cyanogen bromide, chymotrypsin, or trypsin. The fragments obtained in each of the treatments were separated, hydrolyzed ...
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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 ...
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108 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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55 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 ...
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36 views

Question concerning 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 ...
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87 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 ...
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68 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 ...
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How to estimate reaction products of competitive binding?

I have an two reactions, $A + C \rightleftharpoons AC$ $B + C \rightleftharpoons BC$ I'd like to estimate relative steady state proportions $\frac{[BC]_{SS}}{[AC]_{SS}+[BC]_{SS}}$ and ...
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66 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 ...
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100 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 ...
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30 views

Does dehydration synthesis break peptide bonds [closed]

What exactly does dehydration synthesis do. I know it forms water but how. Does it have to break up polysaccharides to do this?
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49 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?
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What's the difference between alpha-glucose and beta-glucose?

What's the difference between $\alpha$-D-glucose and $\beta$-D-glucose? Are they isoforms? Or do they differ in their elemental composition?
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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 ...
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77 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 ...
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Will Mg(II) or Fe(III) be more active in Catechol-O-methyltransferase? [closed]

There is an enzyme called COMT that catalyses this reaction: where SAM is a cofactor and M is a metal atom. In case ...
2
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1answer
34 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 ...
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57 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?
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105 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 ...
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28 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.
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Isothermal titration calorimetry - Ligand binding to protein-protein interface

There is a ligand that binds to the interface of cytoplasmic regions of two different integral membrane proteins. Is it possible to use ITC to determine the affinity of proteins to each other and ...
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84 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?
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70 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)?
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92 views

$\beta$-mercaptoethanol molarity

I'm writing up a practical and $\beta$-mercaptoethanol was used, with no concentration given. I've found I don't need the BME molarity since I'm giving percentage (v/v) concentration, however I'm ...
6
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1answer
81 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 ...
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36 views

How accurate are protein receptors

Has there been any published data on how sensitive and specific protein receptors are to contact and pressure caused by binding? I'm working with HIV-RT and I'm wondering how similar to a nucleotide ...
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33 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, ...
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colloidal osmotic pressure?

The oncotic pressure or colloidal osmotic pressure is the osmotic pressure developed due to the presence of colloids in a solution. But since the colloids are not true solution, why should the ...