Notes on...

Calculating the molecular weight

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

The equation for the molecular weight of a peptide.

where Ni are the number, and Mi the average residue molecular weights, of the amino acids. MN + MC 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:

A, Ala 71.07793 C, Cys 103.1454 D, Asp 115.0873 E, Glu 129.1139
F, Phe 147.1734 G, Gly 57.05138 H, His 137.1394 I, Ile 113.1576
K, Lys 128.1724 L, Leu 113.1576 M, Met 131.1985 N, Asn 114.1028
P, Pro 97.11508 Q, Gln 128.1293 R, Arg 156.1861 S, Ser 87.07733
T, Thr 101.1039 V, Val 99.13103 W, Trp 186.2095 Y, Tyr 163.1728
H 1.00797 OH 17.00738 phos-Ser 167.0573
Acetyl 43.04453 Amide 16.0228 phos-Thr 181.0838
Biotin 227.3056 phos-Tyr 243.1528

Copyright © 2012 Innovagen AB. Contact us!