自己Google了好久，根据：
http://www.sciforums.com/showthread.php?t=43238
http://www.cerocscotland.com/forum/fun-games/6926-word-disassociation.html
http://www.usingenglish.com/forum/ask-teacher/5380-longest-words.html
发现最长的英文单词是：

包含267钟氨基酸的一种蛋白质，共1909个字母

Tryptophan synthetase A protein, an enzyme that has 267 amino acids, and makes a record of 1,909 letters. The chemical notation is

Quote:

methionylglutaminylarginyltyrosylglutamylserylleuc ylphenylalanylalanylglutaminylleucyllysylglutamyla rginyllysylglutamylglycylalanylphenylalanylvalylpr olylphenylalanylvalylthreonylleucylglycylaspartylp rolylglycylisoleucylglutamylglutaminylserylleucyll ysylisoleucylaspartylthreonylleucylisoleucylglutam ylalanylglycylalanylaspartylalanylleucylglutamylle ucylglycylisoleucylprolylphenylalanylserylaspartyl prolylleucylalanylaspartylglycylprolylthreonylisol eucylglutaminylaspfraginylalanylthreonylleucylargi nylalanylphenylalanylalanylalanylglycylvalylthreon ylprolylalanylglutaminylcysteinylphenylalanylgluta mylmethionylleucylalanylleucylisoleucylarginylglut aminyllysylhistidylprolylthreonylisoleucylprolylis oleucylglycylleucylleucylmethionyltyrosylalanylasp araginylleucylvalylphenylalanylasparaginyllysylgly cylisoleucylaspartylglutamylphenylalanyltyrosylala nylglutaminylcysteinylglutamyllysylvalylglycylvaly laspartylserylvalylleucylvalylalanylaspartylvalylp rolylvalylglutaminylglutamylserylalanylprolylpheny lalanylarginylglutaminylalanylalanylleucylarginylh istidylasparaginylvalylalanylprolylisoleucylphenyl alanylisoleucylcysteinylprolylprolylaspartylalanyl aspartylaspartylaspartylleucylleucylarginylglutami nylisoleucylalanylseryltyrosylglycylarginylglycylt yrosylthreonyltyrosylleucylleucylserylarginylalany lglycylvalylthreonylglycylalanylglutamylasparaginy larginylalanylalanylleucylprolylleucylasparaginylh istidylleucylvalylalanyllysylleucyllysylglutamylty rosylasparaginylalanylalanylprolylprolylleucylglut aminylglycylphenylalanylglycylisoleucylserylalanyl prolylaspartylglutaminylvalyllysylalanylalanylisol eucylaspartylalanylglycylalanylalanylglycylalanyli soleucylserylglycylserylalanylisoleucylvalyllysyli soleucylisoleucylglutamylglutaminylhistidylasparag inylisoleucylglutamylprolylglutamyllysylmethionyll eucylalanylalanylleucyllysylvalylphenylalanylvalyl glutaminylprolylmethionyllysylalanylalanylthreonyl arginylserine

太强悍了
好像没什么意义啊？