Measures of leucine aminopeptidase can be used to anticipate UV-induced age-related damage to lens proteins: ascorbate can delay this damage.
This paper focuses on damage to soluble lens proteins during ultraviolet (UV) light exposure and its prevention by ascorbate (Vitamin C). Using 2.3 X 10(-3) W/cm2 UV A and 0.4 X 10(-4) W/cm2 UV B, aminopeptidase inactivation in lens supernatants is significant after 60 min. Protein aggregation and decreases in tryptophan levels, phenomena associated with UV-induced and cataract-related damage, are observed only after longer (6 h) UV exposure. Thus, it would appear that measurements of aminopeptidase activity can be used to anticipate damage to lens structural proteins. Ascorbate (15 mM) added to soluble lens proteins prior to photoirradiation can prevent some of these changes. The data presented suggest plausible relationships between impaired proteolysis and cataract formation.
Laboratory for Nutrition and Cataract Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111.
J
J
Blondin
A
A
Taylor
D000375:Aging / Q000502:physiology*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D003459:Crystallins / Q000378:metabolism / Q000528:radiation effects*; D007700:Kinetics; D007908:Lens, Crystalline / Q000378:metabolism; D007931:Leucyl Aminopeptidase / Q000378:metabolism*; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism; D014466:Ultraviolet Rays
D003459:Crystallins; D014364:Tryptophan; D007931:Leucyl Aminopeptidase; D001205:Ascorbic Acid