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Two different B‐type creatine kinase subunits dimerize in a tissue‐specific manner
Author(s) -
Quest Andrew F.G.,
Eppenberger Hans M.,
Wallimann Theo
Publication year - 1990
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(90)80214-4
Subject(s) - chromatofocusing , isoelectric point , dimer , creatine kinase , amino acid , biochemistry , isoelectric focusing , protein subunit , biology , thermolabile , peptide sequence , microbiology and biotechnology , peptide , chemistry , enzyme , organic chemistry , gene
Brain‐type creatine kinase B‐CK (EC 2.7.3.2) was purified from several chicken tissues, e.g. cardiac muscle, brain, gizzard and retina. Two major monomeric chicken B‐CK subunits, designated Bb (basic) and Ba (acidic), which differ in isoelectric point, were separated by chromatofocussing in the presence of 8 M urea on a MonoP column. The two subunits were shown by peptide mapping, amino acid analysis and partial sequencing, as well as by immunological criteria, to be distinct B‐CK polypeptides. The N‐tenninal sequence of 30 amino acid residues of Bb correspond entirely to data derived from a B‐CK c‐DNA clone termed H4 [(1986) Nucleic Acids Res. 14, 1449‐1463], whereas the N‐terminus of the acidic Ba species was blocked. Native dimeric B‐CK isoenzymes obtained from these tissues were separated by ion exchange chromatography on a MonoQ column yielding two B‐CK dimer populations, type‐I and type‐II B‐CK, varying in relative proportions. Quantitation of the CK activity peak ratios of these two populations revealed the existence of a tissue‐specific, post‐translational mechanism regulating B‐CK dimerization in neural tissues. Tissue‐specific dimerization of the two distinct B‐CK monomer species may represent a means of specifying the intracellular distribution of the dimeric B‐CK subspecies.