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Autolysis of bovine enteropeptidase heavy chain: evidence of fragment 118–465 involvement in trypsinogen activation
Author(s) -
Mikhailova Anna G,
Rumsh Lev D
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01656-1
Subject(s) - enteropeptidase , autolysis (biology) , trypsinogen , chemistry , enzyme , biochemistry , protease , cleavage (geology) , peptide , trypsin , biology , fusion protein , recombinant dna , gene , paleontology , fracture (geology)
Variations in bovine enteropeptidase (EP) activity were shown to result from autolysis caused by the loss of calcium ions; the cleavage sites were determined. The native enzyme preferred its natural substrate, trypsinogen ( K M =2.4 μM), to the peptide and fusion protein substrates ( K M =200 and 125 μM, respectively). On the other hand, the truncated enzyme composed of the C‐terminal fragment 466–800 of EP heavy chain and intact light chain did not distinguish these substrates. The results suggest that the N‐terminal fragment 118–465 of the enteropeptidase heavy chain contains a secondary substrate‐binding site that interacts directly with trypsinogen.