You might like to refer to the original Kent paper that describes "In situ
neutralisation in Boc-chemistry solid phase peptide synthesis" (Schnolzer et
al Int J Peptide Protein Res 40 1992 180-193.
The ratios used were 0.8 mmol Boc-AA
2 ml 0.38 M HBTU (0.76 mmol) in DMF
1.2 mmol DIEA
activate 2 min
add to protonated resin
couple 10 min.
Important points:
Molar ratio AA to HBTU important because excess of HBTU will cause chain
termination.
DIEA should be in excess (I use up to 40% excess over moles AA).
I do not know how stable the AA/HBTU/DIEA stock is. I prepare fresh before use.
Hope this information helps. But you should refer to the paper for more detail.
Regards,
Juan
>We are going to do a manual solid phase peptide
>synthesis and will use HBTU/HOBt/DIEA
>to form esters and to couple amino acids together.
>The ratios we thought to use is
>1:1:1:2 (Fmoc-aa/HBTU/HOBt/DIEA) in DMF.
>
>I have two questions about the coupling reaction.
>
>Does anyone have any suggestions about how long
>the reaction time shall be, if you want to form
>an ester bond or a peptide bond?
>
>Can a stock solution of HBTU/HOBt/DIEA
>in DMF be made, to which you add the amino acid
>when you want to make the coupling step?
>When you have added the amino acid, shall you let the
>solution activate for a while before adding it to the
>solid phase. If that's the case, how long should the
>activating time be?
>
>If you can make up the above mentioned stock solution,
>does somebody know for how long it will be stable?
>
>If there is any other information about the reagents that
>you want to share, please do so.
>
>Best regards Maria Thyboll
>Maria Thyboll
>Department of Analytical Chemistry
>Royal Institute of Technology
>Teknikringen 36
>100 44 Stockholm
>SWEDEN
>Tel +46 8 7906410
>Fax + 46 8 108425
>Email k93_mtl@k.kth.se
>
>
>
Dr. Juan A. Cooper Malaria Biology/Peptide Unit
Queensland Institute of Medical Research Phone : 61 7 3362 0416
The Bancroft Centre, P.O. Royal Brisbane Hospital Fax : 61 7 3362 0104
Herston, Brisbane, QLD 4029 AUSTRALIA E-mail: juanC@qimr.edu.au