Resveratrol is an antioxidant found in grapes and other plants. It has been reported to have health benefits including anticarcinogenic activity and protection against coronary heart disease. Previous methods for its quantification in wines have relied on HPLC and GC. However, an alternative method utilizing capillary electrophoresis (CE) has been developed in our laboratory. The CE procedure resolves cis- and trans-resveratrol isomers, using a micellar mode of separation. The detection limit for resveratrol was 1.25 µM using UV detection at 310 nm. This procedure was employed for the direct analysis of trans-resveratrol in wines. The direct analysis method used was advantageous because the analysis time was greatly reduced and sample preparation procedures that might result in resveratrol isomerization were avoided. The CE procedure was used to determine the level of trans-resveratrol in several California red wines, and the values obtained were in close agreement with those reported using other methods.
Cathepsin D is an aspartyl protease of lysosomal origin and functions in a variety of roles including protein turnover, catabolism of peptide hormones, antigen processing and presentation, and neoplastic disease. In breast cancer, the level of cathepsin D has been linked to metastasis and prognosis for survivability. Many of these studies concerning the role of cathepsin D in cancer have used immunological detection methods to determine the level of enzyme. These indirect methods to assess the cathepsin D level may not reflect enzyme activity accurately. The significance of cathepsin D to physiological and pathophysiological processes suggests that rapid and sensitive methods for determining cathepsin D activity would contribute to a more complete assessment of this enzyme in its various roles. This work describes a procedure to determine cathepsin D activity based on hydrolysis of fluorescently labeled hemoglobin and employs capillary electrophoresis to separate and measure the products of reaction. A single major cleavage product, representing the first 32 residues of the hemoglobin alpha-chain, appeared after a very short incubation time (less than 10 min) and was used to determine activity. The procedure described here requires very small sample volumes, has a low detection limit (approximately 10(-9) M) and thus represents an additional approach to determine cathepsin D activity in biological samples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.