Protein Glycation and Cataract: A Conformational Disease.

Increased glycation is associated with aging and complications of diabetes. So it is not surprising that glycation has been a subject of intensive study. Most emphasis is on long-lived proteins, mostly structural, because they are exposed to the sugars for a longer time than enzymes and other nonstructural proteins in most tissues. However, glycation is not specific and is not restricted to structural proteins. Besides leading to the functional impairment of modified proteins, glycation was shown to produce significant structural alterations, resulting in modified proteins with properties similar to those of "molten-globule" intermediates of protein folding and unfolding pathways. Evidence supporting the role of nonenzymic post-translational modification of lens proteins in cataract is overviewed. [ABSTRACT FROM AUTHOR]