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METABOLIC PARAMETERS OF ONTOGENESIS OF ELECTRICAL ACTIVITY IN THE BRAIN. SODIUM‐POTASSIUM ACTIVATED ADENOSINE TRIPHOSPHATASE IN DEVELOPING CHICK EMBRYO BRAIN
Author(s) -
Zaheer N.,
Iqbal Z.,
Talwar G. P.
Publication year - 1968
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.1471-4159.1968.tb06840.x
Subject(s) - enzyme , embryo , enzyme assay , ouabain , atpase , ontogeny , adenosine triphosphatase , biology , specific activity , sodium , triphosphatase , biochemistry , potassium , medicine , endocrinology , chemistry , microbiology and biotechnology , organic chemistry
—(1) The activity of the Na‐K ATPase in the particulate fraction of the chick embryo brain has been assayed at different stages of development with the objective of finding whether or not changes in the activity of this enzyme bear any relation to the maturation of spontaneous and evoked electrical activity of the growing chick brain. (2) The specific activity of the enzyme is low on day 6 and it rises rapidly between days 10 and 12, at which time it attains a plateau and remains essentially unchanged from day 12 until day 20. Experimental evidence rules out the possible presence of an inhibitor of the enzyme in 8‐day‐old brain homogenates, suggesting that these developmental changes in the activity of the enzyme may represent new synthesis of enzyme rather than its activation. The period between days 10 and 12 does not represent a unique stage of general protein synthesis. (3) The chick brain particulate enzyme has an optimum activity at pH 7·4 and at 37°. It is optimally activated by a Na + concentration of 100m m and K + concentration of 20 m m . The enzyme is inhibited by ouabain and Ca 2+ . (4) The results have been discussed.