A novel calcium-independent enzyme capable of incorporating putrescine into proteins

Yu H. Tsai, W. F T Lai, Shi Hsien Chen, Leonard R. Johnson

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


A Ca++-independent enzyme capable of incorporating [3H]-putrescine into proteins was detected in the rat intestine mucosa. The Ca++-independent incorporation of [3H]-putrescine into proteins was temperature-, pH-, time-, and dose-dependent. However, this enzyme was absent in the gastric mucosa. Similar to testicular Ca++-dependent transglutaminase, the optimal pH of intestinal Ca++-independent enzyme was 9.0. At 10-5 M or less putrescine concentrations, the Ca++-independent enzyme in an intestinal cytosol preparation showed a greater activity than did the Ca++-dependent transglutaminase. However, at higher putrescine concentrations, the latter showed a greater activity than did the former. Both the intestinal Ca++-dependent and independent enzymes were inhibited by cystamine, thermal labile at 50°C and precipitated by 30 to 50% saturation of ammonium sulfate. The fact that these two enzymes shared many similar characteristics, with the exceptions of Ca++-requirement, suggests that they may have similar active site and intrinsic molecular function(s).

Original languageEnglish
Pages (from-to)161-166
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - Mar 6 1998


  • Colon
  • Intestine
  • Mucosa
  • Polyamines
  • Putrescine
  • Stomach
  • Testis
  • Transglutaminase

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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