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Inactivation of cellular caspases by peptide‐derived tryptophan and tyrosine peroxides
Author(s) -
Hampton Mark B,
Morgan Philip E,
Davies Michael J
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)03240-4
Subject(s) - chemistry , singlet oxygen , jurkat cells , tryptophan , peptide , cysteine , caspase , enzyme , biochemistry , tyrosine , apoptosis , thiol , reactive oxygen species , bioorganic chemistry , stereochemistry , oxygen , amino acid , programmed cell death , organic chemistry , biology , t cell , immune system , immunology
Peroxides generated on peptides and proteins within cells, as a result of radical attack or reaction with singlet oxygen, are longer‐lived than H 2 O 2 due to their poor removal by protective enzymes. These peroxides readily oxidize cysteine residues and can inactivate thiol‐dependent enzymes. We show here that Trp‐ and Tyr‐derived peptide peroxides, generated by singlet oxygen, inhibit caspase activity in the lysates of apoptotic Jurkat cells. N ‐Ac‐Trp‐OMe peroxide was the most effective inhibitor, and was 30‐fold more effective than H 2 O 2 under identical conditions. As such, protein peroxides could modulate the progression of apoptosis in cells in which they are generated.