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Guinea Pig Brain Histamine N ‐Methyltransferase: Purification and Partial Characterization
Author(s) -
Matuszewska Bozena,
Borchardt Ronald T.
Publication year - 1983
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.1471-4159.1983.tb11821.x
Subject(s) - sephadex , chromatography , chemistry , isoelectric point , size exclusion chromatography , histamine , sodium dodecyl sulfate , affinity chromatography , gel electrophoresis , polyacrylamide gel electrophoresis , biochemistry , biology , enzyme , endocrinology
Histamine N ‐methyltransferase (EC 2.1.1.8) was purified 4400–fold in 12% yield from guinea pig brain. The basic steps in the purification included differential centrifugation, calcium phosphate adsorption, DEAE‐cel‐lulose chromatography, and affinity chromatography on an S ‐adenosylhomocysteine‐agarose matrix. The resulting protein was homogeneous by gel electrophoresis and was stable for at least 3 months at 80°C. It had an apparent molecular weight of 29 ,000 ± 1000 as determined by both gel filtration through Sephadex G‐100 and by electrophoresis in sodium dodecyl sulfate‐polyacrylamide gels. The isoelectric point of the protein was found to be 5.3. The pH optima for methylation of histamine were determined to be 7.5 and 9.0; the K m s for histamine and S ‐adenosyl‐l‐methionine were 13.57 ± 0.74 μ M and 6.1 ± 0.12 μ M , respectively; the K i for S ‐adenosyl‐l‐homocysteine was 24.5 ± 1.45 μ M .