[Jones]

I've checked several of the answers on here but couldn't see something that satisfied me. I've been asked to draw the structural formula for the reactants and products of Glycine + Valine. After that, I had to label the functional groups and linkages present, as well as show the peptide bond.


R1 = H and R2 = CH, w/ two branches leading to two CH3
Carboxyl = COOH Amino = NH2
Amino Acid (1) = Glycine Amino Acid (2) = Valine Dipeptide = Gly-Ala

My question is, is this right and have I fully answered the question?

[Babcock_Hall]

Are there any other functional groups present?

[Jones]

If we were to look at the -OH then we can say that there is another functional group; hydroxyl.

That's all I can think of, do you see any other functional groups?

[Babcock_Hall]

Yes, but the -OH group is directly bonded to a carbonyl group (C=O), and when we put the two together we get a carboxylic acid.  There is one other functional group present, and it's on the opposite side of the molecule.

[Jones]

There's a carboxylic and an Amino group, but that's all I can think of/see. Am I missing something?

[Babcock_Hall]

Yes, the amino group is the other functional group that I was thinking of.

[Jones]

Does that mean that I have everything answered and accurate?
I just realized that Glycine and Valine both have the double bond on the Oxygen on the top-so should I switch them? Does it matter where the double bond on the oxygen is?

[Babcock_Hall]

In your answer you have Gly-Ala, which is not the same as what you drew.  In general there are several correct ways to draw a molecule.

[Jones]

If you look at the bottom you'll see that I have the functional groups listed, as well as what stands for R1 (H) and R2 (CH leading to two CH3). Would that make what I drew accurate? What's missing, or can I hand it in?

[Babcock_Hall]

I think that the way that you labeled the side-chains is fine.  I don't see any other problems.

[Jones]

Sorry, but just to make sure: would this structure would be ok, disregarding the fact that the peptide bond, and functional groups aren't labelled?

[hypervalent_iodine]

Seems to me you're still missing the functional group in the middle. Unless I'm missing something about the question or the answer you provided.

[Jones]

I thought that there were only two functional groups, and the peptide bond that joins them together? What functional group am I missing?

[hypervalent_iodine]

I thought that there were only two functional groups, and the peptide bond that joins them together? What functional group am I missing?

The functional group that the peptide forms a part of.

[Jones]

I'm not sure that that makes sense to me?