Lysosomal peptidase measurement by sensitive fluorometric amino acid analysis

S. Taylor, A. L. Tappel

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


A procedure has been developed for the measurement of lysosmal peptidase activity that is based upon highly sensitive fluorometric amino acid analysis. The fluorochrome results from the reaction of phthalaldehyde and mercaptoethanol with amino acids or similar compounds at pH 9.5. The fluorometric method is 10-100 times more sensitive than the colorimetric ninhydrin procedure for the measurement of lysosomal peptidases. The method lends itself to the measurement of any peptidase or protease that yields free amino groups in the product. The method has been applied to the measurement of cathepsin A and lysosomal dipeptidase activity.

Original languageEnglish (US)
Pages (from-to)140-148
Number of pages9
JournalAnalytical Biochemistry
Issue number1
StatePublished - Nov 1973
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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