Metabolism of protein-bound DOPA in mammals.
Protein-bound 3,4-dihydroxyphenylalanine (DOPA) can be generated in mammalian cells by both controlled enzymatic pathways, and by uncontrolled radical reactions. Protein-bound DOPA (PB-DOPA) has reducing activity and the capacity to inflict secondary damage on other important biomolecules such as DNA. This may be mediated through replenishment of transition metals or from catechol-quinone-catechol redox cycles in the presence of cellular components such as ascorbate or cysteine, resulting in amplification of radical damaging events. The generation of PB-DOPA confers on protein the ability to chelate transition metals generating protein 'oxychelates'; this may be amongst the factors, which localise such damage. Tissue levels of PB-DOPA are increased in a number of age-related pathologies such as atherosclerosis and cataract formation. We discuss the detoxification, and the subsequent proteolysis and excretion of components of PB-DOPA. We contrast the fact that in marine organisms, and particularly in extracellular proteins, PB-DOPA and other DOPA-polymers can play important functional roles in adhesion and the provision of tensile properties.
Rodgers
K J
KJ
Cell Biology Group, The Heart Research Institute, 145 Missenden Road, Camperdown, Sydney, NSW 2050, Australia. k.rodgers@hri.org.au
Dean
R T
RT
D000818:Animals; D004295:Dihydroxyphenylalanine / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*
D011506:Proteins; D004295:Dihydroxyphenylalanine