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Galactose and glucose metabolism in galactokinase deficient, galactose‐1‐P‐uridyl transferase deficient and normal human fibroblasts
Author(s) -
Friedman Thomas B.,
Yarkin Rhoda J.,
Merril Carl R.
Publication year - 1975
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040850308
Subject(s) - galactokinase , galactosemia , galactose , transferase , metabolism , biochemistry , chemistry , in vitro , biology , enzyme , gene , escherichia coli
Despite the genetic interruption of the Leloir pathway both galactosemic patients and galactosemic fibroblasts can convert galactose to CO 2 and TCA precipitable products, although at less than the normal rate. These observations stimulated investigations into the identity of the alternative metabolic routes which allow for galactose metabolism in the absence of in vitro galactose‐1‐P‐uridyl transferase. Four lines of galactosemic cells, each without detectable gal‐transferase, produced 14 CO 2 from [1‐ 14 C]‐galactose (0.094 μmoles in 20 cc of medium) at approximately 39% ± 16% the rate of transferase positive cells over a 48‐hour period. However, galactokinase deficient fibroblasts produced 14 CO 2 and TCA precipitable products from [1‐ 14 C] ‐galactose or [U‐ 14 C] ‐galactose at only 3% to 9% the rate of normal fibroblasts. Therefore it seems likely that galtransferase deficient fibroblasts must first synthesize galactose‐1‐P for further metabolism of galactose.