TY - JOUR
T1 - Lens hexokinase deactivation by near-UV irradiation
AU - Tung, William H.
AU - Chylack, Leo T.
AU - Andley, Usha P.
N1 - Funding Information:
ACKNOWLEDGEMENTS This work was support,ec! by NIH grants EY0552, EY03247, EY05681, the Brigham Surgical Group Foundation, Alcon Research Institute, and Research t o Prevent B1 indness. The authors thank Ann Piccolomini for administrative support.
PY - 1988
Y1 - 1988
N2 - Photodamage to lens hexokinase has been investigated by exposing the lenses of rat, rabbit and calf eyes to 300 nm irradiation. Hexokinase activity was diminished by 15.9% ± 5.4 and 23.4% ± 5.0 upon irradiation of the isolated rat lens for 1 and 2 hours respectively. Irradiation of the whole eye for 2 hours resulted in hexokinase deactivation of 13.6% ± 5.8 and 19.2% ± 6,2 for rat and rabbit lens homogenates and 55% ± 7 for calf lens capsule plus epithelium. Enzyme deactivation was prevented when the isolated lens was irradiated with the vitreous attached. Glucose, catalase or ascorbate added to the medium prior to irradiation, each had a protective effect on hexokinase deactivation. The results are consistent with a mechanism in which photochemical generation of active species of oxygen, via the photosensitizing action of tryptophan photoproducts, plays a significant role in enzyme deactivation.
AB - Photodamage to lens hexokinase has been investigated by exposing the lenses of rat, rabbit and calf eyes to 300 nm irradiation. Hexokinase activity was diminished by 15.9% ± 5.4 and 23.4% ± 5.0 upon irradiation of the isolated rat lens for 1 and 2 hours respectively. Irradiation of the whole eye for 2 hours resulted in hexokinase deactivation of 13.6% ± 5.8 and 19.2% ± 6,2 for rat and rabbit lens homogenates and 55% ± 7 for calf lens capsule plus epithelium. Enzyme deactivation was prevented when the isolated lens was irradiated with the vitreous attached. Glucose, catalase or ascorbate added to the medium prior to irradiation, each had a protective effect on hexokinase deactivation. The results are consistent with a mechanism in which photochemical generation of active species of oxygen, via the photosensitizing action of tryptophan photoproducts, plays a significant role in enzyme deactivation.
UR - http://www.scopus.com/inward/record.url?scp=0023873070&partnerID=8YFLogxK
U2 - 10.3109/02713688809047031
DO - 10.3109/02713688809047031
M3 - Article
C2 - 3359812
AN - SCOPUS:0023873070
SN - 0271-3683
VL - 7
SP - 257
EP - 263
JO - Current Eye Research
JF - Current Eye Research
IS - 3
ER -