Hey, I'm a biofanatic and I've gotta comment that Tryptophan Synthetase is probably not the longest protein!
Basically, for any protein you can make a sequence of peptide/residue/amino acid names to represent the sequence of that protein, and then call it that! If I recall correctly from my Molecular Biology class last year, there is some protein about 1400 amino acids long, and therefore you could come up with a very long name indeed! These kinds of "words" should probably be discounted, because you can probably artificially make an extremely long peptide chain, and then name it via this nomenclature.
Also, it may be possible to name the entire DNA sequence of a chromosome, over several million base pairs long, via a similar nomenclature in terms of nucleotides! Therefore you could come up with a "word" whose letter count reaches into the tens of millions, if not longer!
Beware the nomenclatures... They are coming after you.... muhahahaha!

THERE ARE NO AMINO ACIDS IN A NUCLEIC ACID!!! take a molecular bio course, or look it up somewheres.... there're plenty of good resources online.

btw, that wasn't supposed to be FLAMING, just a little larger than normal text, and i'm not sure if i'm allowed to html this..... (and i'm not referring to deepa, just some anonymous person who posted earlier on)

anyway, that's interesting, what someone said about using long words to represent biochemical cellular pathways (this is so-called "bioman" speaking again; flattered at that name, i am, btw.)..... That means that the technical words can be long as heck, and actually have some non-repetitive quality to them....

I think that in this discussion it would be reasonable to try to come to a concensus that to avoid something crazy like |example-1| below, we should discount any words that have any of the following properties:


1) Used to describe a chemical compound that is a POLYMER by listing the names of all of its respective monomers, in sequence.

2) Used to describe the relationship between a large set (use your judgement) of elements of a complex, e.g. biologically evolved system.


I just made up those guidelines. Most people posting here have just said "Technical terms". But that encompasses "pneumonoultramicroscopicsilicovolcanoconiosis", which while a descriptive term, is non repetitive in nature and stuff (but so is the biochemical pathways "word"!)..... You guys can decide on that one. But anyway, the point is:

***|--- Who's to decide what "technical" means? ---|***

That's the point.

By the way, as far as "technical" names of chemical compounds that are formed by describing their properties, check out the name of the so-called "sterol nucleus", the core of the structure of all steroid molecules:
PERHYDROCYCLOPENTANOPHENANTHRENE (i learned about that one in my mol. bio. course last year too.)
Isn't it easier just to say "sterol nucleus"?
Just like it's easier to say "chromosome 1 DNA sequence" than jibberjabberblablabla etc., and just like it's easier to say "Tryptophan synthetase" than whatever the hey that long name was. Get it?



|example-1|: Make a really really really long DNA strand with just a repeating sequence, and then give it a full-sequence-nomenclature name or whatever, and it can be millions of letters long! That doesn't seem fair.

-"bioman", as ye call me, evidently.

RANDOM:
In Matsigenka (also spelled Machiguenga), IRAPUSATINKAATSEMPOKITASANOIGAVETAPAAKEMPAROROKARITYO is the longest word. It means: They will probably really go head over heels into the water when they arrive but not stay that way.

Methionylglutaminylarginyltyrosylglutamylserylleucylphen-
ylalanylalanylglutaminylleucyllysylglutamylarginyllysylgluta-
mylglysylalanylphenylalanylvalylprolylphenylalanylyalylthre-
onylleucylglcycylaspartylprolylglicylisoleucyglutamylgluta-
minlserylleucyllysylisoleucylaspartylthreonylleucylisoleu-
cylglutamylalanylglyclyalanylaspartylalanylleucyglutamylle-
ucylgluycylisoleucylproluylphenylalanyserylaspartyprolylleu-
celalanylaspartylglycylprolylthreonylisolleucyglutaminylaspa-
raginylalanythreonylleucylarginylalanylphenylalanylalanylal-
anylglycylvalylthreonylprolylalanylglutaminylcysteinylphen-
ylalanylglglutamylmethionylleucyalanylleucylisoleucylarginyl-
glutaminyllysylhistidylprolyuthreonylisoleucylprolylisoleuc-
ylglycylleucylleucylmethionyltyrosylalanylasbaraginylleucyl-
valylphenylalanylsparaginyyllysylglycylisoleucylaspartylglut-
amylphenylalanylyltyrosylalanylglutaminylcysteinylglutamyll-
ysylvalylglycylvalylspartylserylvalylleucylvallalanylaspart-
ylvalylprolylvalvlglutaminylglutamylserylalanylprolylpheny-
lalalrginylglutaminylalanylalanylleucylarginylhistidylasp-
araginylvalylalalprolylisoleucylphenylalanylisoleucylcystei-
nylprolyprolylaspartylalanylaspartylaspartyspartyleucylle-
ucylarginylglutaminylisoleucylalanylseryltyroslglycylargin-
ylglycyltyrosylthreonyltyrosylleucylleucylserylarginlalanyl-
glycylvalylthreonylglycylalanylglutamylasparaginylarginyla-
nylalanylleucylprolylleucylaspaaginylhistidylleucylvalylalan-
yllysylleucyllysylglutamyltyrosylasparagimylalanylalanypro-
lylprolylleucylglutaminylglycylphenlalanylglycylisoleyucyls-
erylalanylprolylaspartylglutaminylvalyllysylalanylalanylisol-
eucylalspartylalanylglycylalanylalanylglycylalanylasoleucylse-
rylglycylserylalanylisoleucylbalyllysylisoleucylisoleucylgluta-
mylglutaminylhistidylasparaginylisoleucylglutamylpronylglu-0
tamyllysylmethionylluecylalanylalanyoeucyllysylvalylpheny-
lalanylvalylglutamilylprolylmethionyllysylalanylalanylthreo-
nylarginylserine. Now this is the longest word in the world (recorded) at a whopping 1,909 letters