Are peptides considered polymers?

[Mr Rayon]

I know that proteins are polymers but are peptides considered polymers?

[Paralith]

Yes. A peptide basically is a protein, though usually it's used to refer to one segment of a functional protein or the pieces leftover from a partially degraded protein. But it's still a string of amino acids, and thus, a polymer.

[CharonY]

Usually not. While there are no definite rules at which molecular weight something is determined to be a polymer, peptides are generally considered to be too small.

Edit:

Cross posted with Paralith once more. Well you see, there are no definite opinions or rules on that.

[Paralith]

Well, isn't the technical definition of a polymer something that is made up of multiple units? As long as we're talking about a chain of at least two or more amino acids, I would say you have a polymer. I've never heard of a minimum length requirement beyond 2.

[CharonY]

Usually it refers to high-molecular structures consisting of more or less repetitive subunits. Disaccharides, for instance are not considered a polymer, either. But as I said, there is no clear rule when one ends and the other one starts.

Similar like when oligopeptides are starting to called polypeptides.

[CaptainPanic]

Personally I would put peptides in all categories.

A dimer of two monomers will contain one peptide bond. Oligomers will contain a couple, and polymers will contain more than you want to count on your fingers

 

The polymers are often called poly-peptides (as CharonY already said).

[PigStylurian]

hmm are peptides polymers, well in my opinion, no, because peptide polymers are polypeptides

[essence_of_cool]

from what i know... protein is the polymer of amino acids. Peptide bonds join two amino acids together. SO if one can consider a chain of only 2 amino acids a protein, then i think it would be a polymer. But i reckon if its just like a random segment of 2 amino acids for no reason, then calling it a polymer, although techincally correct, is a bit ambiguous as it would have no function but probably to be digested into monomers. I would call small chains polymers only i specifically asked what peptide bonded amino acids TECHNICALLY are.

[ennui]

I'd say that peptides are polymers. Certainly as much as DNA is a polymer. Although you get different R-groups in a peptide (so it might not be an identical repeating unit), you get different bases on DNA.

 

I work in amyloid research. It's a cross-beta repeat of a peptide unit to form a long, fibrous protein. Lots of the literature calls it a polymer.

[CaptainPanic]

I think we all agree that polypeptides are peptides.

 

Since some people suggest that peptides are indeed polymers, these people are suggesting that two amino acids that are connected through a single peptide bond are not a peptide??

 

How about that?

 

I believe that some peptides are polymers, but not all peptides are polymers (2 monomers is not enough to call it a polymer).

[CharonY]

I am not sure where the discussion is moving to. But:

I think we all agree that polypeptides are peptides.

 

Actually polypeptides consist of peptides. I am pretty sure that there is no disagreement that long peptide chains are qualified to be called polymers. Therefore

 

I'd say that peptides are polymers. Certainly as much as DNA is a polymer. Although you get different R-groups in a peptide (so it might not be an identical repeating unit), you get different bases on DNA.

This is not in question.

 

The only ambiguous element is at which size one usually calls them a polymer.

 

I believe that some peptides are polymers, but not all peptides are polymers (2 monomers is not enough to call it a polymer).

Precisely my point.