A few comments:
On 23/02/2000, Steven Johnson wrote:
> You can quite easily do a solution cyclization. Start
> by using Acm protected Cystine. Then, after cleavage
> and isolation, make a 2mg/mL solution in 4%AcOH. Warm
> to about 45C
Heating is not necessary; it is better to run the reaction some longer
> , and hit it (dropwise until the yellow
> colour persists) with a 20mg/mL I2 in methanol
> solution calculated to your quantity of peptide at a
> 1.5 molar ratio. You can follow the cyclization by
> HPLC (disappearance of starting material).
We recently observed a strange effect on an HPLC column (elution of
large peaks with r.t. close to the product analyze but the area and
width about three times higher than normal) after an analysis of
iodine containing mixture. I am not sure it was because of iodine,
but... The column was Luna C18(2) from Phenomenex.
> When done,
> you can purify and desalt your peptide by HPLC.
It is better to remove excess iodine before work-up. Recently we found
it is well absorbed by stirol-DVB resins (we use Dowex).
Vladimir Titov
Bokiron Ltd., Moscow, Russia
This archive was generated by hypermail 2b29 : Thu Mar 16 2000 - 10:06:51 EST