from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An essential amino acid, C11H12N2O2, formed from proteins during digestion by the action of proteolytic enzymes. It is necessary for normal growth and development and is the precursor of several substances, including serotonin and niacin.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An essential amino acid having an indole side chain; it is present in many foods, especially chocolate, oats, bananas and milk; it is essential for normal growth and development and is the precursor of serotonin and niacin; any specific form of this compound, or any derivative of it.
from The Century Dictionary and Cyclopedia
- n. Same as proteinochromogen.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin
tryptic, of trypsin (formed on the model of pepsin, peptic); see trypsin + -phan(e).(American Heritage® Dictionary of the English Language, Fourth Edition)
From German Tryptophan, corresponding to tryptic + Ancient Greek ϕαίνειν ("to appear"). (Wiktionary)