To (big) users of S.c. alpha factor:
We have had good luck as have many others with having alpha factor custom
synthesized. Apparently there is some reason to be concerned about
chemistry that does not screw up the tryptophan(?) in the sequence, but in
two runs, we have gotten back plenty of peptide with good activity. The
price for peptide synthesis varies among suppliers (we use a convenient
in-house service), length of peptide and scale of synthesis. Nonetheless,
I think that you can expect to pay much less than $10 per milligram.
However, unless you are using tens of milligrams at a clip, I recommend
finding some friends to split the bill with, which could easily top $1500
for a big synthesis, which would be most efficient. We payed about $1000
for about 500 mg of moderate purity.
I can't help more than this--I don't know anything about commercial peptide
synthesis services and our in-house service is apparently quite backlogged.
I see adds for $20/residue synthesis in the magazines. Perhaps someone
can suggest a reputable/cheap custom synthesis company...