Output the full name of titin
JavaScript (ES6), 16840 16825 16814 bytes

Saved a couple of bytes by:


inserting the last acid prefix in the packed string as suggested by ETHproductions
choosing the next character group in a slightly more efficient way when there's a tie




Assumes Windows-1252 character encoding. Outputs without a trailing newline.

Below is a simplified version without any actual data.

[...Array(256)].map((_,i)=&gt;i&lt;52|i&gt;126&amp;i&lt;161|i==92|i==96?0:s=s.split(String.fromCharCode(i)).join(`...dictionary...`.slice(j,j+=2)),j=0,s=`...packed_data...`)&amp;&amp;[...s].map(c=&gt;'methion|threon|glutamin|alan|prol|phen|leuc|ser|val|glutam|glyc|histid|isoleuc|tryptoph|argin|aspart|lys|asparagin|tyros|cystein'.split`|`[c.charCodeAt()-32]).join`yl`+'ine'


And here is the full version:

Try it online!

The TIO link includes some additional code to print the MD5 of the output rather than printing the output itself:

ec73f8229f7f8f2e542c316a41cbfff4

How?

This was compressed by:


Mapping the 20 distinct amino acids to ASCII characters 32 to 51.
Repeatedly replacing the most frequent 2-character group by a new ASCII character in the following ranges:


52-91
93-95
97-126
161-255



Which leaves us with a dictionary of 336 bytes (168 entries of 2 characters) and a final compressed string of 16161 bytes.

The above code is doing the exact opposite.