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Evidence for a role of high K m aldehyde reductase in the degradation of endogenous γ‐hydroxybutyrate from rat brain
Author(s) -
Vayer Philippe,
Schmitt Martine,
Bourguig Jean-Jacques,
Mandel Paul,
Maitre Michel
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80426-9
Subject(s) - endogeny , aldehyde reductase , degradation (telecommunications) , chemistry , aldehyde , biochemistry , enzyme , reductase , computer science , telecommunications , catalysis
γ‐Hydroxybutyrate (GHB) is a putative neurotransmitter in brain. We have already demonstrated that it is transformed into γ‐aminobutyrate (GABA) by rat brain slices incubated under physiological conditions. This conversion occurs via a GABA‐transaminase reaction. Therefore, succinic semialdehyde, the oxidative derivative of GHB, appears to be the primary catabolite of GHB degradation. Apparently, the kinetic characteristics and pH optimum of GHB dehydrogenase (high K m , aldehyde reductase) in vitro do not favor a role for this enzyme in endogenous brain GHB oxidation. However, in the presence of glucuronate, glutamate, NADP and pyridoxal phosphate, pure GHB dehydrogenase, coupled to purified GABA‐transaminase does produce GABA from GHB at an optimum pH close to the physiological value and with a low K m for GHB.