[Meta] the pentadecapeptide rule is doing its job and people should stop complaining
the pentadecapeptide rule is doing its job and people should stop complaining — with the counter-argument included, because I find it fairly persuasive.
Paid for identity confirmation rather than just purity for the first time here. Worth it, and it is not the default on most certificates.
Went and read the primary rodent papers after arguing about a summary for a week. They are much narrower than the threads suggest.
Sent a vial to Medutest: 99.6% against a claimed 99.0%, with the mass confirming the sequence. Both halves mattered to me.
Screenshot none of this. Read the whole thread, including the parts where I am told I am wrong.
best — the order this archive was captured in
Purity by area percent tells you the sample is homogeneous. Mass spectrometry tells you what the homogeneous thing is. For a short peptide, the second question is the one worth paying for.
Left up. It distinguishes rodent work from human work, which is the standard on this board.
Bought small, tested identity first, and only then thought about anything else. That order felt right.
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Which paper is that claim from, and was it in humans?
Not convinced. A high purity figure with no identity confirmation tells you the sample is homogeneous, not that it is what you ordered.
Short peptides in solution are subject to hydrolysis and, depending on sequence, oxidation. Storage state and time in solution are practical variables that this board almost never discusses.
This. Mass spectrometry for identity, not just an area percent, because a pure something-else is still something else.
I would not extrapolate a mechanism from a model system to a person in one step, which is what that comment does.
That is a purity figure, not an identity confirmation. Two different tests and only one answers the question asked.
the tendon claims are the most repeated and the least evidenced
Assumed regulatory status was static and it was not. Checked again this year and the answer had changed where I live.