<b>PHOTOCHEMICAL‐LIKE DESTRUCTION OF TRYPTOPHAN IN SERUM ALBUMINS INDUCED BY ENZYME‐GENERATED TRIPLET SPECIES</b>

Abstract

Abstract —Human and bovine serum albumin quench enzyme‐generated acetone phosphorescence ( K sv = ca . 10 4 M 1 ). Concomitantly, these proteins are altered as shown by diminished tryptophan absorption at 280 nm, appearance of products of the formylkynurenine type ( max = ca . 320 nm) and disappearance of tryptophan fluorescence. These alterations—which are similar to those induced photochemically—were also observed with serum albumins exposed to enzyme‐generated triplet acetaldehyde. On the other hand, triplet acetone generated by the thermolysis of tetramethyldioxetane failed to induce alterations. Presumably energy transfer occurs from the enzyme‐generated triplet species to tryptophan group(s) in the serum albumin associated with the acting enzyme. The detailed mechanism is, however, not yet understood.