Open AccessDegradation of Abnormal Proteins in Escherichia coli
Author(s) -
KEMSHEAD John T.,
HIPKISS Alan R.
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb11105.x
Subject(s) - cyanogen bromide , escherichia coli , size exclusion chromatography , chemistry , cleavage (geology) , peptide , protease , molecular mass , biochemistry , alkaline phosphatase , bromide , enzyme , peptide sequence , organic chemistry , biology , paleontology , fracture (geology) , gene
Escherichia coli alkaline phosphatase has been purified and modified by either carboxymethylation or treatment with cyanogen bromide (CNBr). Only the CNBr‐treated protein was degradable in an E. coli cell extract. Separation of the CNBr cleavage products by gel filtration in non‐denaturing conditions gave rise to a number of oligomeric complexes, of which only those of molecular weight less than approximately 29000 were degradable in E. coli cell‐free extracts. Carboxymethylation of the non‐degradable complexes (greater than 29000 molecular weight) resulted in the formation of some complexes of less than 29000 molecular weight: such newly formed complexes were degradable by E. coli cell‐free extracts. It is suggested that E. coli cell‐free extracts may contain a protease/peptidase system which is active against peptide complexes below 29000 molecular weight, but inactive against peptide oligomers of greater molecular weight.