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Ribonuclease activity and substrate preference of human eosinophil cationic protein (ECP)
Author(s) -
Sorrentino Salvatore,
Glitz Dohn G.
Publication year - 1991
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 - 10.1016/0014-5793(91)80994-e
Subject(s) - ribonuclease , polynucleotide , rnase p , cytidine , bovine pancreatic ribonuclease , rna , biochemistry , chemistry , uridine , eosinophil cationic protein , hydrolysis , substrate (aquarium) , pancreatic ribonuclease , enzyme , microbiology and biotechnology , biology , eosinophil , ecology , asthma , immunology , gene
The eosinophil cationic protein (ECP), a potent helminthotoxin with considerable neurotoxic activity, was recently shown to also have ribonucleolytic activity. In this work the substrate preference of ECP ribonuclease action was studied in detail. With single‐stranded RNA or synthetic polyribonucleotide substrates ECP showed significant but low activity, 70‐ to 200‐fold less than that of bovine RNase A. ECP hydrolyzed RNA more rapidly than it did any synthetic polynucleotide. Poly(U) was degraded more rapidly than poly(C), and poly(A) and double‐stranded substrates were extremely resistant. Defined low molecular weight substrates in the form of the 16 dinucleoside phosphates (NpN′) and uridine and cytidine 2′, 3′‐cyclic phosphates were tested, and none showed hydrolysis by ECP at a significant rate. The results link ECP ribonucleolytic activity to the ‘non‐secretory’ liver‐type enzymes rather than to the ‘secretory’ pancreatic‐type RNases.