Asparagine!!

 

Asparagine

MW: 132.12 g/ mol^-1

Asparagine has a chemical formula of C₄H₈N₂O₃.  It can be abbreviated as Asn, or N. The structural name is 2-Amino-3-carbamoylpropanoic acid. In 1806, two chemists isolated this amino acid in a crystallized structure. This was the first of the amino acids to be isolated. Asparagine is a nonessential amino acid (body can make its own supply) that can be found in many proteins as well as plants. This is an important amino acid because it is necessary for the synthesis of many proteins.

The functional groups include an amine, amide, and a carboxylic acid that is a carboxamide (side chain functional group).

This amino acid provides key sites for N-linked glycosylation modification of the protein chain with the addition of carbohydrate chains. Asparagine also plays an important role in the metabolism of ammonia, which is toxic in the human body. The nervous system needs asparagine to maintain balance, as well as in amino acid transformation.

PKa Values

Equation:  pKa = -log Ka

      Ka = [H+] x [X-] / [HX]

The Pka values of Asparagine

            ³Pka of carboxylic acid = 2.02

            ³Pka of amino acid = 8.08

Isoelectric Point

pI = (pKa1 + pKa2)/2

       (2.02 + 8.08) / 2 = 5.41 pH

The isoelectric point for asparagine is 5.41 pH. This means that the amino acid has an equal number of positive and negative charges at this pH level.

IR Spectrum

Synthesis

  

⁴Aparagine is the product of amidation of aspartate. Aspartate is developed into asparagine in an ATP-dependent reaction catalyzed by asparagine synthetase, and glutamine is the amino group donor. The process is shown in the picture below.

Citations:

1.) http://www.chemie.fu-berlin.de/chemistry/bio/aminoacid/asparagin_en.html

2.) http://www.newworldencyclopedia.org/entry/Asparagine

3.) http://www.cem.msu.edu/~cem252/sp97/ch24/ch24aa.html

4.) http://www.rpi.edu/~bellos/new_page_2.htm

BLAH.... THE TEST!!!

So... the test didn't go so well. I thought my score was going to be a little higher than it was but there was many questions on the test that I thought were way too hard. I think that a class like this should be graded by how well you understand something. The questions to me are way to in depth and could be a little easier. We went through chapter 14 extremely fast for my likings and could have spent a few more days on the HNMR and CNMR spectrums in my opinion. Also, I feel like if we had a test review day things would go much better. Another factor for not doing well on the test was the need of more time. I felt very rushed and yes! I understand that eventually some of us will take tests like this that are timed but at the same time I think because this is an actual class we should have accurate time to do the problems and questions.

Some questions on the test that i didn't expect to do were number 15 and number 11. I think these questions are doable but could be worded differently and broken down. I think that time could have been saved on question 15 if the graphs were given and then we provided the different frequencies, the same for number 13.

I expected to see more questions that were similar to our sapling homework. There were a lot of Sapling problems and I feel like doing them didn't really prepare me much for this test even though on the past test I think Sapling did provide with studying assistance. A question that I really thought would have been on the test was counting the number of signals CNMR and HNMR for each compound. That was kind of a simple question but yet would have given us a chance for some easy points. Every test needs a few of those.

I did horrible on this first test, but I think with tutoring i maybe okay next test. I am doing pretty much all of the practice problems so therefore i should do decent I hope.

Muddiest Point!

             So I have had a couple muddiest points thus far... Electromagnetic radiation is really confusing. I cant really grasp the understanding of the equations but i found information on Wikipedia that can provide me assistance (http://en.wikipedia.org/wiki/Electromagnetic_radiation).
        Also I cant figure out how you are supposed to  match a compound to a given mass spectrum. With more reading i have found out that you have to  look at each of the wavelengths and the peaks to determine which compound is which.
        I am not 100 percent sure about the base points and highest points of individual mass spectra. I found a great website that explains this little by little. (http://www.chemguide.co.uk/analysis/masspec/fragment.html#top)
I think with more studying and reading i will be prepared for this test hopefully.