Amino Acid Mass Table

Here's the set of monoisotopic and average amino masses and elemental mass values we use in our tools developed here. The amino acid masses are based on the sum of the elemental masses where the elemental masses are from Unimod. You can also download this spreadsheet where the average and monoisotopic masses for each amino acid are calculated within the spreadsheet from the listed elemental values (that you can change). Structure images are from Wikipedia or Wikimedia. Please send me an email if you find an error!

Click on structure header for larger (viewable!) images.
Click on column headers to sort these tables:
amino acid code 3LTR composition mono mass avg mass structure
glycine G GLY C2H3NO 57.021463735 57.05132
alanine A ALA C3H5NO 71.037113805 71.0779
serine S SER C3H5NO2 87.032028435 87.0773
proline P PRO C5H7NO 97.052763875 97.11518
valine V VAL C5H9NO 99.068413945 99.13106
threonine T THR C4H7NO2 101.047678505 101.10388
cysteine C CYS C3H5NOS 103.009184505 103.1429
leucine L LEU C6H11NO 113.084064015 113.15764
isoleucine I ILE C6H11NO 113.084064015 113.15764
asparagine N ASN C4H6N2O2 114.042927470 114.10264
aspartic acid D ASP C4H5NO3 115.026943065 115.0874
glutamine Q GLN C5H8N2O2 128.058577540 128.12922
lysine K LYS C6H12N2O 128.094963050 128.17228
glutamic acid E GLU C5H7NO3 129.042593135 129.11398
ornithine O ORN C5H12N2O2 132.089877680 132.16098
methionine M MET C5H9NOS 131.040484645 131.19606
histidine H HIS C6H7N3O 137.058911875 137.13928
phenylalanine F PHE C9H9NO 147.068413945 147.17386
selenocysteine U SEC C3H5NOSe 150.953633405 150.3079
arginine R ARG C6H12N4O 156.101111050 156.18568
tyrosine Y TYR C9H9NO2 163.063328575 163.17326
tryptophan W TRP C11H10N2O 186.079312980 186.2099

elementcodemono massavg mass
hydrogen h 1.007825035 1.00794
carbon c 12.0000000 12.0107
nitrogen n 14.003074 14.0067
oxygen o 15.99491463 15.9994
phosphorus p 30.973762 30.973761
sulphur s 31.9720707 32.065
proton 1.00727646688

modificationresiduesmono massavg masscomposition
phosphorylation STY 79.966331 79.9799 HO3P
oxidation M 15.994915 15.9994 O
acetylation K 42.010565 42.0367 H2C2O
carbamidomethyl C 57.021464 57.0513 H3C2NO