I was just wondering, can the zwitterion of amino acids be actually observed in the 1H NMR spectrum? If yes, can you please tell me any special feature? If no, how can I track amino acid zwitterions? Thanks!
126043
The amino and carboxyl protons are very difficult to observe. Using 100% D2O will replace the carboxyl and amino protons with 2H, and you won't see anything. Use a different solvent and you can't be sure you are in the zwitterion form (pH is difficult to control in non-aqueous solutions and you will get different hydrogen bonding)\n\nIf you really want to see those protons your best bet would be to use 90% H2O / 10% D2O with either phosphate buffer or the perdeuterated buffer of your choice (you can get these from Cambridge Isotopes). Make sure the buffer concentration is large compared to your amino acid, and make sure you have adjusted the pH to the zwitterion range. When you aquire the spectrum you will need to use a water suppression sequence. Presat is the easiest, although I much prefer gradient selected 3-9-19. This still may not be enough to see the protons-- if they are exchanging the linewidth may become so broad as to disappear into the baseline.\n\nWhile it's difficult to observe the carboxyl and amino protons (they are *very* sensitive to solvent and pH) you should be able to see changes in the chemical shifts of the remaining protons, particularly the alpha protons.\n\nIf you are really interested, make a sample of your favorite amino acid and take spectra over a range of pH. Plot the chemical shifts of the visible protons as a function of pH and the shape of the curve should allow you to determine the pKa of the amino and carboxyl groups. Here you could get away with just using D2O, which makes the spectroscopy much simpler.\n\nGood luck and have some fun with this!
30418
Exactly what it makes depends on how the molecules are hooked together--sugars and amino acids are complex and can be joined in multiple spots.  Amino acids are used primarily to build proteins, and some proteins have sugars added to them--this is particularly common for proteins that are placed on the cell surface.  It is also common for phosphates to be added to amino acids, and this is often used as a switch; a protein might be off until a phosphate is added to an amino acid, or vice versa.    A similar process is ADP-ribosylation, in which a molecule consisting of an adenine, 2 ribose sugars and 2 phosphates is added to an amino acid in a protein.  Some toxins such as pertussis toxin inactivate their cellular target through ADP-ribosylation.\n\nOne type of molecule that is similar to what you are asking about is a nucleotide.  It contains a sugar and a phosphate, but not an amino acid; instead it has a nitrogenous base (A, C, T, or G).
416577
Protein synthesis is not the simplest process, but I will try to keep this answer as simple as possible.  Here I present a highly simplified reduction of the process of protein synthesis.\n\nmRNA made in the nucleus of a cell is transported to the cytoplasm of a cell.  When mRNA is in the cytoplasm the ribosome assembles around it.  The ribosome is composed of two subunits, a small ribosomal subunit and a large ribosomal subunit.  Each of the subunits is composed of rRNA and proteins.  The two ribosomal subunits will bind to the ribosome binding site (rbs) of the mRNA.  The rbs is located prior to the open reading frame of the ribosome. When the ribosome binds to the mRNA the ribosome begins to move down the mRNA.  \n\nDuring this time tRNA is binding to the mRNA as well.  tRNA simply carries the amino acid that will compose the protein to the mRNA so that the amino acids of the protein can become bound to one another.  \n\nSo as the ribosome moves down the mRNA it will encounter tRNA.  However, the tRNA's amino acids will not be bound together until the ribosome reads a mRNA sequeunce that indicates an open reading frame is present. An open reading frame is the sequence of mRNA that is translated into protein sequence.  So once an open readin frame is indicated to be present the ribosome moves down the mRNA until it reaches the start codon.  Protein synthesis begins at hte start codon.  At the start codon the tRNA specifying methionine is present.  Methionine will be the first amino acid in any protein because the methionine codon is also the start codon.  So the methionine tRNA will move into the A site.  At this site the ribosome will ensure that the correct tRNA is bound to mRNA.  If the correct tRNA is bound then the ribosome A site moves onto the next codon and the tRNA just found to be correct will move into the P-site, in this case the methionine tRNA will move into the P-site.  The tRNA that just moved into the A-site will now be checked to see if it is the correct tRNA.  When the tRNA is found to be correct then the amino acid on the tRNA in the p-site will form a peptide bond with the amino acid on the tRNA from the a-site. The amino acid chain is connected to the tRNA in the a-site as the amino acid that was connected to the p-site tRNA becomes disconnected as it forms a peptide bond with the a-site tRNA's amino acid. Then the ribosome moves down the mRNA again.  The tRNA from the p-site moves to the e-site and it is allowed to exit the ribosome.  The p-site and a-site perform the same function as before and the peptide chain will get longer until the ribosome reaches a stop codon.  Once the ribosome reaches a stop codon the peptide chain will no longer increase in size.  The ribosome will then move until it finds another start codon or until the mRNA sequence indicates that it should dissociate.
521907
Denaturation usually occurs with boiling or mild reaction conditions; a, c, and d will alll occur. These are all relatively weak bonds. However amino acid sequence will remain, you need harsh conditions to break these strong peptide bonds.\nb) is answer
277091
Maybe this is of any help?\n\nhttp://www.chemistry.nmsu.edu/studntres/chem435/Lab7/intro.html
670661
Sounds like somebody is working on a biochem lab. :) \n\nDenaturation lowers enzyme activity because it changes the shape of the protein. Heat disrupts the tertiary structure by breaking covalent, non-covalent and van der waals interations between side chains of the protein. Proteins must be in the right conformation in order to perform their functions correctly. When they are denatured substrates can no longer bind to the active site, key amino acids are no longer in the correct position. \n\npH affects enzyme activity in the following ways: 1-enzyme binding to the active site 2-catalytic activity 3-ionization of the substrate 4-variation of protein structure. This is because pH will change the ionization state of certain side chains. (H+ ions will interact with \n\nOptimum conditions for alpha amylase (ptyalin) from wikipedia.com:\n Optimum pH-5.6 - 6.9\n Room temperatue- 37 degrees Celsius
182203
We don't detect amino acids in stars directly, they need a much cooler environment to form and stay together.  We have found them in asteroids and comets within our own solar system, and have observed them in clouds of insterstellar gas.\n\nThe "we are all made of stardust" comment comes from the relization that all of the elements heavier than hydrogen and helium are created in the cores of stars, or in the violent deaths of some stars.  All the elements that make up you, me, this planet, everything were formed inside of stars and then blown out upon the cosmos to be reincorporated into new structures.  Kind of neat actually.
129428
The wavelength of absorbance for a peptide bond is 190-230nm.\n\nRetrieved from "http://en.wikipedia.org/wiki/Peptide_bond"\n\nI couldn't find any info on the other compounds - sorry!
174107
Here's a good site:http://www.accessexcellence.org/RC/VL/GG/protein_synthesis.html\n\nAnd here another with a movie to explain it:http://www.lewport.wnyric.org/jwanamaker/animations/Protein%20Synthesis%20-%20long.html
529257
No it is irreversible. Once the Nitrogen hydrocarbon link of aminoacids is destroyed, it could not be reformed.
295960
Look at their conjugate bases and whichever is more stable will have the weakest acid. PKA values are also easy to prove this becuase it is a realtion of the H+ content.
522052
Philippe Verbiest, the lawyer for cycling's world governing body, confirmed Tuesday that a carbon isotope ratio test, which detects a subtle chemical difference between the natural and synthetic versions of testosterone, was done. The New York Times has reported the test detected the man-made hormone, but Verbiest refused to give any details of the result. \n\nThe test focuses on carbon atoms in testosterone molecules. These atoms come in different types, called isotopes. The ratio of one particular isotope to another isotope is different in synthetic versus natural testosterone. The test detects that difference. \n\nWhen the lab procedure is performed correctly it is very accurate, said Dr. Don Catlin, the director of the UCLA Olympic doping lab. He helped develop the test. Dr. Gary Wadler, an internist and author with expertise in the area of drug use by athletes, said he's not aware of anything other than synthetic testosterone that will produce a positive test result. \n\nWhen athletes take synthetic testosterone to boost performance, it typically helps them get stronger, recover faster from workouts, prevent tissue breakdown and increase their assertiveness, said Wadler, a member of the World Anti-Doping Agency who stressed he was not speaking for that group. \nVR
195411
http://www.lloydminsterheavyoil.com/nitrogen.jpg\nhttp://www.tcm.phy.cam.ac.uk/castep/MD/img43.png
584405
Amino acid is One of the 20 building blocks of protein. The sequence of amino acids in a protein and, hence, the function of that protein are determined by the genetic code in the DNA. \n\nAmino acids are molecules that (in technical terms) contain a basic amino (NH2) group, an acidic carboxyl (COOH) group and a side chain attached to an alpha carbon atom. \n\nThe 20 amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. \n\nMost dietitians say it is unhealthy for people but it depends on blood count and things like that you should ask you physician or doctor before you do anything
449561
Yes, you're somewhat right.. It's just a replacement of the 6 water molecules with 6 ammonia molecules.\n\nBut for each 'step' in a synthesis you must start with the product of the PREVIOUS step. So rewrite your equations.\n\nBy the way you're missing the chlorine in your equations as well.
143024
Amino Acids = C, H, N, O, S (in a few side chains)\nNucleotides = C, H, N, O, P\nLipids = C, H, O \nCarbohydrates = C, H, O\nWater = H, O\nIons = Na (and Cl, K, Fe, Cu, Zn, etc.)\n\nWith those, you can build pretty much any other biomolecule.
418142
this maybe helpful \n\n\n\nwww.springerlink.com/index/R617G25W81437Q01.pdf\n\nhttp://www.springerlink.com/index/R617G25W81437Q01.pdf