Mystery dermorphan analog?

[Mystylplx]

Mystery dermorphin analog?

Hi guys, I think this is my first post here. I was wondering if you could help me figure out a bit of a mystery. I don't know a lot of chemistry so I was hoping more knowledgeable people might have some insight. So here it is--

A bunch of those biochem sites are selling what they simply call "dermorphin analog." The sequence is TYR-d-ARG-PHE-SAR-TYR-PRO-SER-NH2. The thing is I have been unable to find any published studies on this particular compound. Maybe I'm not looking right. Maybe they call it something else in the studies, but when i google the sequence all that comes up is company after company that are selling it, but no studies. Pubmed returns zero results.

Odder still is that several of the sites contain the same description--

The dermorphin-derived peptide [Dmt1] dermorphin analog labels m-opioid receptors with high affinity and selectivity in receptor binding assays. In mice, radiant heat tail-flick assays, [Dmt1] dermorphin analog produces profound spinal and supraspinal analgesia, being approximately 5000 and 100 times more potent respectively than morphine in causing these analgesia on a molar basis. When administered systemically, [Dmt1] dermorphin analog has been shown to be over 200 times more potent than morphine.

The thing is that is almost verbatim a description of a different analog. The peptide being described is H-Dmt-D-Arg-Phe-Lys-NH2. And this isn't just one site--there's a bunch of them selling the tyr--d-arg analog and using almost the same verbatim description. Are those somehow the same peptide? What am I missing?

I know you guys must get tired of chemistry illiterates asking dumb questions, so thanks VERY much for any help figuring this out.

 

[Mystylplx]

So does this mean it's as much a mystery to everyone here as it is to me? I was hoping there was some rational explanation that I just wasn't aware of but that those more knowledgeable in chemistry would be.

 

[sekio]

The "dermorphin analog" looks like Dermorphin but with the glycine swapped for sarcosine.

Dmt(1)DALDA is another, completely seperate peptide.

 

[Mystylplx]

The "dermorphin analog" looks like Dermorphin but with the glycine swapped for sarcosine.

Dmt(1)DALDA is another, completely seperate peptide.

Yes, I know, which is why I'm trying to figure out why so many biochem co's are selling the one with the description of the other. (Though the DALDA analog is described as a dermorphin analog also in the studies on it. It's an analog fragment) I've emailed a few of them but so far am getting the run-around. The DALDA analog is reported to be around 4 times as potent as dermorphin itself and to show minimal cross tolerance with other opiods. It's patented, however, so is not for sale anywhere.

 

[nuke]

Is it more stable in regards to proteases in vivo with the sarcosine substitution?

Edit: Hey hey hey, here is the paper it is from
http://www.febsletters.org/article/S0014-5793(98)00545-6/abstract
Apparently it's an analogue of a peptide found in frog skin.

2nd edit: It gets weirder.. The paper has the following peptide listed

YXFHLMD [paper]
YXFZYPS [yours]

where x is a d-amino acid, z is sarcosine

The ones in the paper are all delta receptor ligands
...what is this thing? There are two papers in pubmed detailing sarcosine analogues of dermorphin, but they are all four AAs long in length.

 

[Mystylplx]

I could be misunderstanding this, but my impression is the D-x at the 2 position is what makes it stable re proteases. Though substituting sar for gly could make it more stable in terms of storage? And yeah, I don't know where this one came from but a bunch of sites are selling it and using the description of the DALDA analog. That's the weirdest part. Not all sites selling it use that description, but a bunch do. It comes almost word for word from an abstract of testing done on the DALDA analog. There's a link to the abstract in question in the OP.

I'd include links to some of the sites selling it and using the description from the DMT1 DALDA analog, but I know that would be against the rules. But if anyone just googles the entire description they'll be there.

BTW, there are a bunch of these dermorphin analogs out there and dermorphin is the one found in frog skin. Dermorphin itself is supposed to be 40-50X the potency of morphine, but not 200X when administered systemically.