Notes on...

Calculating the molecular weight

The molecular weight M of a peptide may be estimated by calculating

where N_i are the number, and M_i the average residue molecular weights, of the amino acids. M_N + M_C are added to the total in order to account for the termini: H at the N-terminus and OH at the C-terminus. Of course, if the termini are modified, these additions are replaced by those of the modifiers.
The resulting molecular weight depends on what values the algorithm uses. Some of the values Innovagen's Peptide Calculator uses are:

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