ACETYLSERYLTYROSYLSERYLISOLEUCYL-
THREONYLSERYLPROLYLSERYLGLUTAMINYL-
PHENYLALANYLVALYLPHENYLALANYLLEUCYL-
SERYLSERYLVALYLTRYPTOPHYLALANYL-
ASPARTYLPROLYLISOLEUCYLGLUTAMYLLEUCYL-
LEUCYLASPARAGINYLVALYLCYSTEINYL-
THREONYLSERYLSERYLLEUCYLGLYCYL-
ASPARAGINYLGLUTAMINYLPHENYLALANYL-
GLUTAMINYLTHREONYLGLUTAMINYLGLUTAMINYL-
ALANYLARGINYLTHREONYLTHREONYL-
GLUTAMINYLVALYLGLUTAMINYLGLUTAMINYL-
PHENYLALANYLSERYLGLUTAMINYLVALYL-
TRYPTOPHYLLYSYLPROLYLPHENYLALANYL-
PROLYLGLUTAMINYLSERYLTHREONYLVALYL-
ARGINYLPHENYLALANYLPROLYLGLYCYL-
ASPARTYLVALYLTYROSYLLYSYLVALYLTYROSYL-
ARGINYLTYROSYLASPARAGINYLALANYLVALYL-
LEUCYLASPARTYLPROLYLLEUCYLISOLEUCYL-
THREONYLALANYLLEUCYLLEUCYLGLYCYL-
THREONYLPHENYLALANYLASPARTYLTHREONYL-
ARGINYLASPARAGINYLARGINYLISOLEUCYL-
ISOLEUCYLGLUTAMYLVALYLGLUTAMYL-
ASPARAGINYLGLUTAMINYLGLUTAMINYLSERYL-
PROLYLTHREONYLTHREONYLALANYLGLUTAMYL-
THREONYLLEUCYLASPARTYLALANYLTHREONYL-
ARGINYLARGINYLVALYLASPARTYLASPARTYL-
ALANYLTHREONYLVALYLALANYLISOLEUCYL-
ARGINYLSERYLALANYLASPARAGINYLISOLEUCYL-
ASPARAGINYLLEUCYLVALYLASPARAGINYL-
GLUTAMYLLEUCYLVALYLARGINYLGLYCYL-
THREONYLGLYCYLLEUCYLTYROSYLASPARAGINYL-
GLUTAMINYLASPARAGINYLTHREONYL-
PHENYLALANYLGLUTAMYLSERYLMETHIONYL-
SERYLGLYCYLLEUCYLVALYTRYPTOPHYL-
THREONYLSERYLALANYLPROLYLALANYLSERINE
The spelling of the above word was taken from The Insomniac's Dictionary by Paul Hellweg. Thanks to Angela Sosnowski for assisting in the proofreading of the word.
There are two artificial terms describing complex chemical compounds which have appeared in the Guinness Book of World Records. However these "words" have never been used by chemists and have never appeared in a chemical book or paper. Thus, they have been withdrawn from Guinness.
One is a 3,641-letter chemical name describing bovine NADP-specific glutamate dehydrogenase, which contains 500 amino acids.
The other, which appears below, is supposed to be a 1,913-letter chemical name for the tryptophan synthetase A protein:
methionylglutaminylarginyltyrosylglutamylserylleucylphenylalanylalanylglutaminyll
eucyllysylglutamylarginyllysylglutamylglycylalanylphenylalanylvalylprolylphenylal
anylvalylthreonylleucylglycylaspartylprolylglycylisoleucylglutamylglutaminylseryl
leucyllysylisoleucylaspartylthreonylleucylisoleucylglutamylalanylglycylalanylaspa
rtylalanylleucylglutamylleucylglycylisoleucylprolylphenylalanylserylaspartylproly
lleucylalanylaspartylglycylprolylthreonylisoleucylglutaminylasparaginylalanylthre
onylleucylarginylalanylphenylalanylalanylalanylglycylvalylthreonylprolylalanylglu
taminylcysteinylphenylalanylglutamylmethionylleucylalanylleucylisoleucylarginylgl
utaminyllysylhistidylprolylthreonylisoleucylprolylisoleucylglycylleucylleucylmeth
ionyltyrosylalanylasparaginylleucylvalylphenylalanylasparaginyllysylglycylisoleuc
ylaspartylglutamylphenylalanyltyrosylalanylglutaminylcysteinylglutamyllysylvalylg
lycylvalylaspartylserylvalylleucylvalylalanylaspartylvalylprolylvalylglutaminylgl
utamylserylalanylprolylphenylalanylarginylglutaminylalanylalanylleucylarginylhist
idylasparaginylvalylalanylprolylisoleucylphenylalanylisoleucylcysteinylprolylprol
ylaspartylalanylaspartylaspartylaspartylleucylleucylarginylglutaminylisoleucylala
nylseryltyrosylglycylarginylglycyltyrosylthreonyltyrosylleucylleucylserylarginyla
lanylglycylvalylthreonylglycylalanylglutamylasparaginylarginylalanylalanylleucylp
rolylleucylasparaginylhistidylleucylvalylalanyllysylleucyllysylglutamyltyrosylasp
araginylalanylalanylprolylprolylleucylglutaminylglycylphenylalanylglycylisoleucyl
serylalanylprolylaspartylglutaminylvalyllysylalanylalanylisoleucylaspartylalanylg
lycylalanylalanylglycylalanylisoleucylserylglycylserylalanylisoleucylvalyllysylis
oleucylisoleucylglutamylglutaminylhistidylasparaginylisoleucylglutamylprolylgluta
myllysylmethionylleucylalanylalanylleucyllysylvalylphenylalanylvalylglutaminylpro
lylmethionyllysylalanylalanylthreonylarginylserine
Fredrik Viklund writes, "Chemical terms should not in my opinion be listed as long words. Many, many compounds are so complex that their names would be horrific and probably beat the ones listed in all known sources. It is exceedingly hard to reconstruct the correct structure from the name, and many attempts are made to automate the process from structure to name and vice versa. Some systems are successful and commonly used in database searching. The long words starting with ACETYL-SERYL-TYROSYL-SERYL- methionyl-glutaminyl-arginyl-tyrosyl-glutamyl- are spelled-out versions of the amino acid sequence of proteins. To have the longest word, it would only require finding a larger protein, and as proteins are discovered at a rate of hundreds to thousands per week it wouldn't be sporty to accept those names as 'words.' Similar spelling-out for DNA sequences would yield even longer words as the DNA is continous for up to several hundred million bases where each base would be named something like 'uracilphosphate.'"
John Carroll provides the words DIISOBUTYLPHENOXYETHOXYETHYLDIMETHYLBENZYLAMMONIUMCHLORIDE and METHYLCHLOROISOTHIAZOLINONE (27 letters). The latter substance is found in Pert Plus shampoo.