Free epsilon amino groups and 5-hydroxymethylfurfural contents in clear and cataractous human lenses.
The free epsilon-amino groups and 5-hydroxymethylfurfural (5-HMF) contents were determined in soluble and insoluble proteins of clear human lenses and diabetic and nondiabetic senile cataractous lenses. The free epsilon-amino group content of soluble proteins in diabetic cataracts was decreased by 37% (P less than 0.01), whereas in nondiabetic senile cataracts it did not differ from that of clear lenses. The free epsilon-amino group content of insoluble proteins both in diabetic and nondiabetic cataracts was decreased significantly (P less than 0.001, P less than 0.015, respectively). The 5-HMF content of soluble proteins in diabetic cataracts was increased by 52% (P less than 0.001), whereas in nondiabetic cataracts it did not change from that of clear lenses. The 5-HMF content of insoluble proteins in diabetic as well as in nondiabetic cataracts was increased significantly as compared to that of clear lens (P less than 0.001, P less than 0.001, respectively). The soluble protein of diabetic and nondiabetic cataracts was decreased with an increase in the insoluble protein content. These results suggest that nonenzymatic glycosylation plays a role in the conformational change of lens proteins in both diabetic and nondiabetic cataracts.
D002386:Cataract / Q000209:etiology / Q000378:metabolism*; D003459:Crystallins / Q000378:metabolism; D048909:Diabetes Complications; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007908:Lens, Crystalline / Q000378:metabolism*; D012995:Solubility
D003459:Crystallins; C008046:5-hydroxymethylfurfural; D005662:Furaldehyde