PURPOSE : At ARVO 95 (#2422), we described HPLC/EC as a technique for simultaneously determining [H2O2], and the major water soluble antioxidants (WSAs) in NZ White rabbit AH: L-cysteine, L-ascorbic acid, glutathione and uric acid. Also reported, was an unknown species with a retention time (RT) of 13 min. METHODS and RESULTS: Based upon RT, I/V curve, pH titration, MW by dialysis and mass spec, chemical properties previously reported, and elimination with the enzyme mushroom tyrosinase, the unknown species is L-tyrosine, a known hydroxyl radical scavenger via aromatic hydroxylation. It's concentration at 100 uM is significant compared to other AH antioxidants, and second in electrochemical activity to AA. (Graph Presented). CONCLUSIONS: L-Tyrosine is an antioxidant at significant concentration in mammalian aqueous humor. Plans include determinination of "pecking order" for small MW aqueous humor WSAs in the physiol. relevant range of UVR and po2. Support: EY0730, AOF and IL. Soc. Prev. Blindness.
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - 15 Feb 1996|