The Longest Word in the English Language

It's massive, and it's got to do with your body. It also makes these two sentences looks sheepishly at their feet, in terms of length. What is this monstrosity you ask? 

 Methionylglutaminylarginytyrosylglutamylserylleucylphenylalanylalanylglut-
aminylleucyllysylglutamylarginyllysylglutamylglycylalanylphenylalanyvalyl-
prolylphenylalanylvalythreonylleucylglycylaspartylprolyglycylisoleucylglut-
amylglutaminylserylleucyllysylisoleucylaspartylthreonylleucylisoleucylglut-
amylalanylglycylalanylaspartylalanylleucylglutamylleucylglycylglycylisoleu-
cylprolylphenylalanylserylaspartylprolylleucelalanylaspartyglycylprolythreo-
nylisoleucylglutamiylasparaginylalanylthreonylleucylarginylalanylphenylalan-
ylalanylglycylvalyltheonylprolylalanylglutaminylcysteinylphenylalanygllutam-
ylmethionylleucyalanylleucylisoleucylarginylglutaminyllysylhistidylprolylthre-
onylisoleucylpriIylisoleucylglycylleucylleucylmethionyltyrosylalanylasparag-
inylleucylvalyphenylalanylasparaginyllysylgyycylisoleucylaspartylglutamylph-
enylalanyltyrosylalanylgutaminyllcysteinylglutamyllysylvalylglycylavlylaspart-
ylserylvalylleucylvalylalanylaspartylvalyprolylvalylglutaminylglutamyllserylal-
anyprolyphenylalanylarginylglutaminylalanylalanylleucylarginylhistidylaspara-
ginylvaylalanylprolylisoleucylphenylalanylisoleucylcysteinylprolylprolylaspart-
ylalanylaspartylaspartylaspartylleucylleucylarginyglutaminylisoleucylalanyyls-
eryltyrosylglycylarginylglycyltyrosylthreonyltyrosylleucylleucylserylarginylal-
anylglycylvalythreonylglycylalanylglutamylasparaginylarginylanylalanylleucyl-
prolylleucylaspaaginylhistidylleucylvaylalanyllysylleucyllysylglutamyltyrosyla-
saraginylglycylphenylalanylglycylisoleucylalanylprolylaspartylglutaminylvalyl-
lysylalanylalanylisoleucylaspartylalanylalanyglycylalanylalanyglycylalanylisol-
eucylserylglycyserylalanylisoleucylbalyllsylisoleucylisoleucylglutamyyylgluta-
minylhistidylasparaginylisoleucylglutamylprolyglutamyllysylmethionylleucyla-
lanylalanylleucyllysylvalylphenylalabylvalylglutaminlylprolylmethionyllysylala-
nylalanylthreonylarginylserine 

It's the scientific name for Tryptophan synthetase, which is a protein containing 267 amino acids. It contains 1,846 letters. Take that, supercalifragilisticexpialidocious.