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Cleavage of Rabbit Myelin Basic Protein by Plasmin: Isolation and Identification of the Major Products
Author(s) -
Law Mona J.,
Deibler Gladys E.,
Martenson Russell E.,
Krutzsch Henry C.
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb05548.x
Subject(s) - rabbit (cipher) , plasmin , isolation (microbiology) , myelin , cleavage (geology) , myelin basic protein , identification (biology) , chemistry , biochemistry , biology , central nervous system , enzyme , neuroscience , microbiology and biotechnology , botany , computer science , paleontology , fracture (geology) , computer security
Rabbit myelin basic protein (BP) was subjected to partial cleavage with plasmin, and 15 cleavage products were isolated by a combination of gel filtration and ion‐exchange chromatography. Their identification was achieved by amino acid analysis and tryptic peptide mapping, supplemented in some instances by carboxy‐terminal analyses with carboxypeptidases A, B, and Y and amino‐terminal analyses with dipeptidyl aminopeptidase I. The results showed that major plasmic cleavage sites included the Lys 89 ‐Asn 90 , Lys 133 ‐Ser 134 , and Lys 153 ‐Leu 154 bonds. Cleavages also occurred at the Arg 31 ‐His 32 , Lys 53 ‐Agr 54 , and Arg 25 ‐His 26 bonds, but these appeared to be less extensive. A large number of additional peptides were produced in relatively low yield. The smaller of these were isolated from heterogeneous fractions by high‐voltage electrophoresis‐TLC. Amino acid analysis of these peptides showed that minor cleavage sites included the Arg 9 ‐His 10 , Lys 13 ‐Tyr 14 , Lys 103 ‐Gly 104 , Lys 137 Gly 138 , Lys 140 ‐Gly 141 , and Arg 160 ‐Ser 161 bonds. In spite of a lower selectivity toward peptide bonds in BP as compared with pepsin, cathepsin D, and thrombin, plasmin has the advantage over the former proteinases in that it does not cleave at or near the Phe 44 ‐Phe 45 bond. Instead it cleaves at the Arg 31 ‐His 32 and Lys 53 ‐Arg 54 bonds, thus preserving the entire hydrophobic sequence Ile‐Leu‐Asp‐Ser‐Ile‐Gly‐Arg‐Phe‐Phe as well as short sequences to either side.