Any estimation formula for calculating peptide yield before starting synthesis? if there give me a formula with explanation.
For example. Resin loading capacity is 0.71mmol /SPPS
for achieving 100mg of peptide how much amount of amino acid need to take for coupling.
Lorraine,
Please forgive me... Do you think that the yield of the (di)peptide you are talking about might be a little better if the cleavage from resin procedure you use was slightly improved?
Dear Lorraine Clark.,
Nice answer but you have said about only 20%yield it's too low. normally i will get yield >45% for polypeptide up to 29amino acids. and up to 10amino acid i will get sure .65% yield from FMOC-SPPS. and i have did peptide up to 42sequence but yield 25%around. just by sequence capacity wise calculation is better but for polypeptide it's most complicated so i have asked.
For Peptide yield improvement you use improved Fmoc Chemistry means it gived good result.
Thank for your Reply...
Good Luck And Regards
R.Selva....
Dear Selva.,
Based on resin capacity, how much individual amino acid % attached to the resin calculation is best method. yah some more complicated in polypeptide synthesis but it will give efficient result. one new formula is there but right now i forget. i will update it soon..
Have A Nice Think.
I Also agree individual calculations will give better result, some confusion and difficulty is there for calculating polypeptide but give better result.
Hi Selva,
Lorraine Clark gave a very well explanation for calculation.Yield are usually low about 20-30%. but you need to know the sequence and mol wt to calculate theoretical yield. and it's best to use low loading resins if you have a long sequence.
Good luck.
Dear Lorraine Clark,
Nice justification for SPS yield calculation of yours. I am working with PNA synthesis with longer sequence length like 24 mer. Can you please clarify why you are considering 20% theoretical yield in your calculation or I can take any lower value below 25% ??
To calculate loading of first amino acid on CTC resin, you can do the following
1 Weigh about 10 mg of loaded resin in plastic syringe fitted with PEG filter
2 Add 200 micro litre of 20% piperidine
3 Shake 10 minutes
4 collect filtrate in 25 ml volumetric flask
5 repeat steps 2 to 4 one more time
6 complete the volume to 25 using ethanol
7 read sample versus blank on UV spectrophotometer @301 nm
Blank: 400 micro litre of (20% piperidine in DMF) in 25 ml ethanol.
Loading = (abs*flask volume) / (7.8*wt)
(7.8 L/mmol cm) is the extinction coefficient of the dibenzofulvene-piperidine adduct at 301 nm
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