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AN IMPROVED METHOD FOR THE MEASUREMENT OF 14 CO 2 APPLIED TO A PROBLEM OF CYSTEINE METABOLISM IN SQUID NERVE
Author(s) -
Hoskin F. C. G.,
Pollock M. L.,
Prusch R. D.
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.tb04348.x
Subject(s) - hypotaurine , squid , taurine , cysteine , chemistry , metabolism , liquid scintillation counting , biochemistry , biophysics , radiochemistry , biology , enzyme , amino acid , ecology
—A method has been developed for the measurement of metabolically evolved 14 CO 2 which reduces contamination, utilizes conventional scintillation counting equipment, and makes possible direct comparisons with liquid samples without the need for large correction factors. The application of the method reveals that cysteine is transported into squid axons where much of it is decarboxylated, but where very little of the remainder of the molecule is metabolized to CO 2 . In contrast, pyruvate is taken up much more slowly, probably by diffusion, but is almost entirely metabolized to CO 2 . Thus cysteine does not appear to be appreciably metabolized by squid nerve via a ‘pyruvate pathway’. Although only a little appears to be metabolized via a ‘taurine pathway’, that small portion goes mainly to hypotaurine, and none goes beyond to isethionate.