Figure 1. Chromatogram of protein-free extract from lenses of 15-day-old OXYS rat. The peaks marked by arrows are identified as kynurenine (KN), tryptophan (Trp), and N-acetyl-tryptophan (NAc-Trp). The inserts show absorption spectra of KN (5.9 min) and Trp (10.2 min) found in lenses, paired with the spectra of standard compounds (dashed lines).