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Cleavage of Myelin Basic Protein by Neutral Protease Activity of Human White Matter and Myelin
Author(s) -
Berlet Hans H.,
Ilzenhöfer Heike,
Schulz Günther
Publication year - 1984
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.1471-4159.1984.tb12781.x
Subject(s) - proteolysis , myelin , proteases , biochemistry , protease , chemistry , myelin basic protein , gel electrophoresis , sodium dodecyl sulfate , polyacrylamide gel electrophoresis , enzyme , biology , central nervous system , neuroscience
Polypeptides arising from neutral in vitro proteolysis of myelin basic protein (MBP) of human brain were evaluated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. At pH 7 a marked breakdown of MBP resulted in the formation of 8–12 polypeptides ranging from 6 to 17 kd in molecular weight. As neutral proteolytic activity was not eliminated by either gel filtration or cation‐exchange chromatography acid‐soluble protease(s) involved probably have a size and electric charge similar to that of MBP. The enzymatic nature of neutral proteolysis was ascertained by heat inactivation and inhibition by α 2 ‐macroglobulin. Incomplete inhibition of proteolysis and the failure of small peptides (< 6 kd) to show up on electrophoresis seem to suggest that MBP was degraded by exopeptic proteases as well. Acid extracts of purified myelin yielded polypeptides similar to those of MBP of delipidated white matter. The results are consistent with a sequential limited proteolysis of MBP by neutral proteases probably associated with myelin and possibly related to the in situ catabolism of MBP in man.