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BIOSYNTHESIS OF MYELIN PROTEINS IN VITRO 1
Author(s) -
Smith Marion E.,
Hasinoff Catherine M.
Publication year - 1971
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.1471-4159.1971.tb12004.x
Subject(s) - myelin , cycloheximide , biochemistry , proteolipid protein 1 , in vitro , leucine , chemistry , myelin proteolipid protein , protein biosynthesis , biosynthesis , biology , myelin basic protein , amino acid , central nervous system , endocrinology , enzyme
— The rates of uptake of DL‐[1‐ 14 C]leucine into the three classes of protein in myelin isolated from slices of rat brain and spinal cord were determined. Basic protein exhibited the slowest rate of uptake; chloroform‐methanol‐soluble proteolipid protein exhibited intermediate rates and the insoluble protein had the most active uptake. All myelin proteins were less active than the mixture of proteins derived from the non‐myelin fraction. Cyclohexi‐mide (10 −3 M) and choramphenicol (5 × 10 −3 M) inhibited the incorporation of [1‐ 14 C]leucine into brain proteins by as much as 95 per cent. γ‐Aminobutyric acid had no effect on the system. Chloramphenicol also inhibited the uptake of [1‐ 14 C]acetate into myelin lipids, but cycloheximide did not affect lipid synthesis. These effects were observed on both 35‐day‐oldand 18‐month‐old rats, but the biosynthetic activity was far less in myelin from the older rats. The results are discussed in relation to the structure of myelin. It is suggested that the data best fit models in which lipid and protein are in separate phases in the membrane.