Amino acids Definition and 35 Threads

In https://en.wikipedia.org/wiki/Selenocysteine , I read: "As of 2021, 136 human proteins (in 37 families) are known to contain selenocysteine (selenoproteins)." This seems to indicate (my knowledge of biochemistry being close to zero) that this amino acid is not found throughout the human...

The pH stays the same because the optimum pH of trypsin is around pH 7.5. I think??

We lyophilized 50mg/ml mAb with PI of 7.5 in a 10mM His buffer pH 6.2. Upon reconstitution the pH is 6.5. Does anyone have an explanation for this? I am under the impression His is much less susceptible to pH change during lyophilization as opposed to something like a phosphate buffer. Thanks.

Hello, Are the 20 amino acids that are usually referenced when building genetically coded proteins in all of life, and no other amino acids or are these only in humans and animals? I found the sentence below on this website and I wasn't sure what to make of it, is it true that there are...

Homework Statement Suppose you were told you had a protein with molecular mass of 65,000 g/mol. Show how you would estimate the number of amino acids present in this protein. Keep in mind that you cannot calculate the exact number, the point of this is to approximate how many amino acids are...

It is said that of the 20 amino acids that body needs to produce it's proteins, 9 are not made by the body, so they need to be given in the form food. My question is, is the said nine are not all produced by the body, or are the body produces them, albeit very little which is not enough?

I was wondering whether it is possible for amino acids that end up in a cell (ready to be made into proteins) to spontaneously start to bond in the cytoplasm (or wherever the routing channel is I guess) and create randomly floating short strands of polymers? Furthermore, can it ever happen that...

After having a debate with somebody about amino acids found in space, they replied, " As for the amino acids, we simply have no evidence that they can actually form in space -- it is indeed quite a ridiculous assertion. I am reminded of a PhD named Hugh Ross who actually talked about something...

In nature, do right and left handed amino acids act like magnets in that right and left bind more readily than left + left or right + right? Do amino acids bind with each other, creating functional proteins without the help of other molecules/catalysts? At what temperatures/pressures does...

I got a question, consuming amino acid and consuming protein is the same thing right? Protein is a chain of amino acids but it does not really change their properties by becoming protein right?

Just wondering what the physical size of amino acids such as glycine and alanine are in nm or Angstroms. Thanks.

Chemists claim to have solved riddle of how life began on Earth http://phys.org/news/2015-03-chemists-riddle-life-began-earth.html Here is the journal article http://www.nature.com/nchem/journal/vaop/ncurrent/full/nchem.2202.html

I have been trying to get my head around the basics for these four (Carbohydrates, Proteins, Amino Acids and Lipids) for about a week and I just don't understand the basic structure, formulas and such. Help?!

Hi forum goersI'm reviewing some coursework for my General Chemistry class and cannot seem to find a reasonable explanation of why amino acids exist as zwitterons in solid state and ph7 solutions. I'm fairly certain the explanation has to do with its solubility in water, but I am not sure. Here...

Hello! I'm having a hard time understanding the acidity and basicity of amino acids. I read this: the acidic group in an amino acid is NOT the -COOH but the NH3+ and the basic group is COO- and not the NH2... why? Thanks in advance!

I'm doing a lab and my biology teacher specifically told me to count the amino acids found in the hemoglobin of the aforementioned animals. Since I'm sure I'm not the only one who'd rather not count, and I cannot for the life of me find the numbers on the Internet, I figured I would post what...

Homework Statement How does the following reaction demonstrate an amino acid as an acid: H2NCH2COOH + CH3OH → H2NCH2COOCH3 + H2O How does the following reaction demonstrate an amino acid as a base: H2NCH2COOH + CH3COCl → CH3CONHCH2COOH + HCl Homework Equations The Attempt at a...

hi, I've got a problem,which 3 amino acids are non-chiral ? I know there are many of them but I suppose they're only asking about those which are in organisms... I know about glycine but what are the other two ? thanks

We all know an amino acid consists of a carbon atom with an amine group, a carboxylic acid group, and a hydrogen atom. Also attached to this carbon is an 'R' group, which varies from amino acid to amino acid. My question regards the 'R' group. If the R group can be anything from a hydrogen...

I was wondering whether anyone knows an experiment relating to bodybuilding protein shakes. I want to find out which amino acids are present within the protein shake by doing an experiment but i have no clue what how to carry it out. The protein is in powder form. I was thinking of...

I need to compare amino acid R chains relative to each other. Is there a way to figure this out with the chemical forumula or am i supposed to glance over the stuctures? Also I am finding mixed messages about polarity for each. Are these correct? thanks lab test rf...

Homework Statement Estimate the volumes of the various amino acids in units of nm^3 Homework Equations V = 4/3*pi*r^3 The Attempt at a Solution Is it alright to treat the amino acids as spheres? Using this I was thinking of measuring the distance, atomic radii and bond length...

Checked google no satifying answer.Thanks :smile:

Hello everyone, My biochemistry book just says there are 20 amino acids that are essential and not synthesizd by the body. Then it doesn't say how other amino acids are synthesized. My guess is they are synthesized from transamination reactions of essential amino acids. Does that mean if you...

Hello, I use some standard tables of amino acids pKa values, as the one here: http://www.cem.msu.edu/~cem252/sp97/ch24/ch24aa.html and I am especially interested in the pKr (i.e. pKa of the side chains). Correct me if I'm wrong, but pKa values listed in such tables refer to a "free" peptide...

Homework Statement The following structures illustrate hydrogen bonding interactions between amino acid side chains and/or backbone atoms within a protein structure. In which of the following figures are the structures and hydrogen bonding completely correct? Homework Equations...

Homework Statement What mechanism is responsible for the sequencing of amino acids? Homework Equations The Attempt at a Solution I don't quite understand, is it asking what is the procedure called that causes sequencing of amino acids?

http://www.sciencedaily.com/releases/2008/02/080228174823.htm This seems exciting for origin of life research.

i am doing revision for my exams aand was wondering which one of these, high temperature, hydrolysis or pH change would break the ionic bond between amino acids. I would go for pH change. I have no reason, it's just instinctively.

How can you tell if a given amino acid is acidic or basic? I'm lost here. My first thought would be to look at the pKa values. There is virtually no difference in the pKa values for the carboxyl groups; all range from 1.82-2.38. The same goes for the pKa values of the amino groups; all range...

Is it okay to eat pure amino acids or can they cause disease?

-------------------------------------------------------------------------------- Hi there When talking about limiting amino acids what does it really mean... What I think it means is say we have a food eg wheat it has all the essential amino acids (aa) in it except one of them is not...

What is a beta amino acid and how would a beta amino acid look like? I know that the beta carbon is the second carbon from the functional group but which group would be where? Can I have an example of a beta amino acid?

Bio Help! what is the difference between amino acids on their own and amino acids that have been incorporated into a polypeptide chain? My answer is that amino acids on their on do nothing. However when they interact they create a protein which eventually takes on a particular function...

lol, I hope that a donkey bridge is a used term in English? I'll explain it, just in case.. it is to make an associative link between things to be remembered. Is there any easy way to learn the structures of all the 20 aminoacids and whether they are polar/nonpolar/charged? It would be...