Use of fluorescamine-labeled casein as a substrate for assay of proteinases

Kazuhiro Sogawa, Kenji Takahashi

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


Conditions have been investigated for the use of fluorescamine-labeled casein as a substrate for fluorometric assay of proteinases. Fluorescamine-labeled casein can be prepared simply by mixing solutions of casein and fluorescamine at pH 8.0 and used without removal of the excess reagent or its hydrolysis product. The fluorescence of the labeled casein and its enzymatic digest is moderately stable in the range of pH 7.0 to 10.0. Activities can be determined by measuring the fluorescence of the hydrolysis products soluble in 0.1 M trichloroacetie acid solution at pH 4.0 after adjusting the pH of the acid-soluble fraction to 7.7. This method is suited for assay of proteinases active at neutral to slightly alkaline pH values, and is capable of quantitating about 0.05 μg of trypsin or 0.5 μg of α-chymotrypsin or papain. The assay can be done in the presence of large amounts of contaminating amino acid, protein and/or exopeptidases which may interfere with the ordinary assay of proteinases.

Original languageEnglish
Pages (from-to)1783-1787
Number of pages5
JournalJournal of biochemistry
Issue number6
Publication statusPublished - 1978 Jun
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


Dive into the research topics of 'Use of fluorescamine-labeled casein as a substrate for assay of proteinases'. Together they form a unique fingerprint.

Cite this