Side chain polarity Reset Display the indole group as Ball & Stick. Add a distance measure (in Å units). Some facts on L-tryptophan. Abbreviation: Trp. One-letter code: W, as in "double ring". Molecular mass: 204 daltons. Side chain (or R-group) features: Structural formula: Formula: -CH2-indole; Category: hydrophobic; aromatic. pKa: none. Return to image of Trp.
Some facts on L-tryptophan.