[Studentofstuff123]

My biochem teacher has claimed no one has ever answered (in all his years of teaching) what this structure with the question mark over it is.  I was wondering if any of you could take a wild guess? I want to see if it's right, of course it's not for points or anything but I was wondering why it was so complicated?  He said even his biochem majors can't figure it out.

Thank you

[Babcock_Hall]

Do you mean what functional group it is?  That is a somewhat different question.  If that is what you mean, then what functional group do you think it is?

[Studentofstuff123]

Yes, he asked what functional group this is.  He is going to give us the answer by Monday but he wanted to see if any of us could figure it out 'by any means necessary'.  I don't think any other student cares to find out, but I am just curious as to why it's so difficult.

I can't find it in my biochem book though.

[Babcock_Hall]

I think that what makes it difficult for me is that I see the overall functional group as the combination two common functional groups.  By itself, the side chain of an asparagine residue is an amide.  If you combine an amine with a hemiacetal derived from a carbohydrate, what do you obtain?

[Studentofstuff123]

I think that what makes it difficult for me is that I see the overall functional group as the combination two common functional groups.  By itself, the side chain of an asparagine residue is an amide.  If you combine an amine with a hemiacetal derived from a carbohydrate, what do you obtain?

I am not sure. I'm kind of lost on this one.  What would be your best guess?

[curiouscat]

Wait till Monday! 

[billnotgatez]

@Studentofstuff123
I was wondering if you read forum rules

[Arkcon]

OK, so ... removing all the rest of the graphic, and drawing it out, (and converting to SMILES so it displays here,)



Is that sort of close to it -- ignoring that the rest of the sugar ring has to be called a CH₃ (I'm not very good at SMILES yet)?  Like everyone else, I see a couple of functional groups, but I don't know a name for this one by itself.  Unless the letters for the atoms spell your school's initials, or something.  Could that be it?

[DrCMS]

I think it should be this

[Babcock_Hall]

@OP, You must make an attempt; that is a forum rule.  However, I will give you a hint.  The functional group that connects a base (purine or pyrimidine) to a ribose or deoxyribose in RNA or DNA respectively, is similar.

[Kikko]

@OP, You must make an attempt; that is a forum rule.  However, I will give you a hint.  The functional group that connects a base (purine or pyrimidine) to a ribose or deoxyribose in RNA or DNA respectively, is similar.

Is it a tertiary amine ?

(but on the first/original question in would be a secondary amine?)

[Dan]

Is it a tertiary amine ?

No, look it up: example of a list I found on google.

In your original post you highlighted this fragment:

[Kikko]

Is it a tertiary amine ?

No, look it up: example of a list I found on google.

In your original post you highlighted this fragment:

I dit not ask it :p
But was curious.
Ah yes, I forgot the O.
I guess its a hemiaminal than?

[Studentofstuff123]

Is it a tertiary amine ?

No, look it up: example of a list I found on google.

In your original post you highlighted this fragment:

I dit not ask it :p
But was curious.
Ah yes, I forgot the O.
I guess its a hemiaminal than?

After reading the list provided, I'm thinking it could be hemiaminal, but that has 5 R groups.  Is it a hemiaminal?

[Dan]

After reading the list provided, I'm thinking it could be hemiaminal, but that has 5 R groups.  Is it a hemiaminal?

The specific linkage in the red box is a hemiaminal - not sure where you are getting 5 R groups from:

You have in this case:


R1 = sugar ring; R2 = sugar ring; R3 = Asn residue of peptide

More specifically (also considering what is outside the red box) you could call this structure an N-acyl hemiaminal (because R3 is an acyl group).

Based on the core amide structure:



and given that R1 = glycosyl, you could call it an N-glycosyl amide. There are a lot of functional groups present, so there is more than one logical way of describing what is present.