Oxytocin is not a protein. It is a peptide made of only 9 amino acids.Originally Posted by Archetypical Hybrid
(HEC)
It has no tertiary structure.
Oxytocin is not a protein. It is a peptide made of only 9 amino acids.Originally Posted by Archetypical Hybrid
(HEC)
It has no tertiary structure.
I think HEC meantOriginally Posted by xvs
the proteins in the peptide..
Originally Posted by Archetypical Hybrid (HEC)
ddddddddddddddddddddddddddddddd
Last edited by Mungojerry; 10-05-2015 at 07:47 AM.
Gentlemen,Originally Posted by Mungojerry
Having been acused on several occassions of getting "too technical," I
suspect we may be pressing the upper limits of technicalities here, but also wanted to add:
From Wikpedia:
(because even I had to check my assumptions)
"a peptide is an amino acid molecule without secondary structure; on
gaining defined structure, it is a protein." Thus the same molecule can be either a peptide or a protein depending
on its environment, though there are peptides that cannot be
proteins."
JVK
Don't trust Wikipedia too much. What we'reOriginally Posted by jvkohl
talking about here are polypeptides, not peptides. A peptide is a single amino acid residue (the amino acid as it is
once it's part of a chain), and a polypetide is two or more amino acids linked together.
Oxytocin is a
9-unit polypeptide.
All proteins are polypeptides, but the primary distinguishing factor between
polypeptides and proteins is whether they have tertiary structure, and this is determined mainly by the number of
peptides. The smallest human proteins which have been identified are about 45 peptides in length.
Proteins
have three structures:
- primary, which is the sequence of peptides (amino acids) in the chain.
-
secondary, which is the linkage between peptides in one part of the chain with peptides in the other part of the
chain (usually through the same hydrogen bonds that keep water liquid at room temperature).
- tertiary, which is
the complete structure of a protein, including all the folding (beta sheets, alpha helixes, etc.)
Oxytocin is
only 9 units long. This is too short to have ANY tertiary structure. So oxytocin is NOT a protein.
But it
does have a secondary structure, as can be seen in this paper:
secondary structure of part of
oxytocin. The dotted lines are hydrogen bonds.
xvs,Originally Posted by xvs
Someday soon we should speak on the phone. I know
that Wikipedia is not the ultimate source, but it's a reasonably good source for info that's easier to understand
than most--especially textbooks.
My primary interest is in the decapeptide hormone: gonadotropin releasing
hormone, which oddly enough has a 9-unit version of its mammalian counterpart in yeast, which is non other that the
alpha mating pheromone of "brewer's" yeast. I think that hormones are considered proteins, but could be wrong--and
also that their receptors are proteins, but could be wrong. We may just be running into definitions that don't help
researchers communicate well across different disciplines. Also, a fraction of the GnRH decapeptide appears to
function directly as a neurotransmitter: a hormone? a protein?
JVK
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