Capillary electrophoretic determination of cathepsin D activity using Oregon green-labeled hemoglobin

Qingyi Chu, Steve Jones, Michael Zeece

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


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 α-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.

Original languageEnglish (US)
Pages (from-to)2945-2951
Number of pages7
Issue number14
StatePublished - 1999


  • Capillary electrophoresis
  • Cathepsin D
  • Protease activity

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry


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