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METHYLATED AMINO ACID RESIDUES OF PROTEINS OF BRAIN AND OTHER ORGANS
Author(s) -
Kakimoto Y.,
Matsuoka Y.,
Miyake M.,
Konishi H.
Publication year - 1975
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.1471-4159.1975.tb03653.x
Subject(s) - lysine , biochemistry , amino acid , histidine , arginine , cerebroside , methionine , biology , chemistry
—Methods for the determination of methyl‐lysine, methyllarginine and methylhistidine residues of tissue proteins are described. They consist of preliminary purification of basic amino acids, enzymic removal of lysine, arginine and histidine followed by amino acid analysis. Recovery rates and specificities of the method were satisfactory. The contents of methylamino acids in proteins of mammalian organs were determined. The distribution of proteins containing the methylamino acids in human brain showed that the concentrations of methyl‐lysine and N G , N′ G ‐dimethylarginine were highest in the gray matter of the cerebellar cortex and relatively high in regions rich in gray matter, while those of N G ‐mono‐ and N G , N′ G ‐dimethylarginine were highest in the white matter. The following findings suggest that most of the N G ‐mono‐ and N G , N′ G ‐dimethylarginine was associated with the myelin basic protein. The distribution of the methylarginine residues of acid‐soluble proteins in bovine brains coincided with the cerebroside pattern. The concentrations of the amino acids in acid‐soluble proteins of rat brain increased concomitantly with the increase of cerebroside. The methylamino acid content in proteins increased during the purification of the myelin basic protein from the white matter of human and bovine brains. Proteins containing N G , N G ‐dimethyiarginine and di‐ and trimethyl‐lysine are concentrated in cell nuclei. The first amino acid was found mainly in nucleoplasmic proteins and the other two were found in histones. The concentration of 3‐methylhistidine residue, highest in muscular proteins, is low in cerebral proteins and is probably derived from proteins of walls of blood vessels in the brain.