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International Journal of Ophthalmology(English edition) 2016年第10期9卷 1506-1517页

作者： Nicola Pescosolido Andrea Barbato Rossella Giannotti Chiara Komaiha Fiammetta Lenarduzzi Department of Cardiovascular RespiratoryNephrologicAnesthesiologic and Geriatric SciencesSapienza University of Rome Department of Sense Organs Sapienza University of Rome

The crystalline lens is a transparent,biconvex structure in the eye that,along with the cornea,helps to refract light to be focused on the retina and,by changing shape,it adjusts focal distance（accommodation）.The three classes of structural proteins found in the lens areα,β,and γ *** proteins make up more than 90% of the total dry mass of the eye *** components which can be found are sugars,lipids,water,several antioxidants and low weight *** ageing changes occur in the lens,it causes a gradual reduction in transparency,presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the *** main changes that occur with aging are： 1） reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2）crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3）production of advanced glycation end products（AGEs）,lipid accumulation,reduction of reduced glutathione content and destruction of ascorbic *** if effective strategies in preventing cataract onset are not already known,good results have been reached in some cases with oral administration of antioxidant substances such as caffeine,pyruvic acid,epigallocatechin gallate（EGCG）,α-lipoic acid and ascorbic ***,methionine sulfoxide reductase A（MSRA） over expression could protect lens cells both in presence and in absence of oxidative stress-induced ***,promising results have been obtained by reducing ultraviolet-induced oxidative damage.

关键词： antioxidants cataract crystalline eye lens kynurenines ultraviolet radiations

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Comparison in effect of different metal ions, pH and reducing agent on the protease activity in human hyper mature and mature cataract

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2007年第8期8卷 599-603页

作者： SAMI Amtul Jamil SAMI Amtul Naseer KANWAL Noreen Institute of Biochemistry and Biotechnology University of the PunjabLahore 54594Pakistan Institute of Ophthalmology King Edward Medical University Lahore 54594 Pakistan

This study was undertaken to isolate and characterize the protease activity of human eye lens sample of mature and hyper mature cataract. Samples were collected just after surgery of the cataract lens and were stored at -20 ℃. The total protein extract was isolated from 5 samples in each case （mature and hyper mature cataract） and clear supernatant obtained after centrifugation was used as an enzyme source. The optimum pH for the proteases of mature cataract was 7.5 while the proteases of hyper mature cataract were recorded for maximum activity at pH 5.5 and 7.5. The optimum temperature for both enzyme sources was 50 ℃. Effect of different metal ions such as potassium, lead, silver, zinc and borate was studied. In each case protease activity was increased. Reducing agent e.g. β mercaptoethanol also caused an increase in activity indicating the involvement of sulfhydryl groups. Protease activity was also located on agar plates.

关键词： Mature cataract Hyper mature cataract eye lens Protease activity β mercaptoehanol

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