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PROPERTIES OF THIAMINE DI‐ AND TRIPHOSPHATASES IN RAT BRAIN MICROSOMES: EFFECTS OF CHLORPROMAZINE
Author(s) -
Iwata H.,
Baba A.,
Matsuda T.,
Terashita Z.
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.tb03900.x
Subject(s) - chlorpromazine , microsome , thiamine , chemistry , imipramine , enzyme , desipramine , reserpine , biochemistry , medicine , endocrinology , pharmacology , biology , hippocampus , alternative medicine , pathology , antidepressant
— The mechanism of the action of chlorpromazine on rat brain thiamine phosphatases were studied to clarify the properties of these enzymes in the CNS. Chlorpromazine at concentrations of 0.25‐1.0 m m caused marked decrease of microsomal and soluble thiamine triphosphatase (TTPase) activities and marked increase of microsomal thiamine diphosphatase (TDPase) activity. Imipramine and desipramine also inhibited TTPase but did not cause any marked change in TDPase activities. Addition of chlorpromazine (0.5 m m ) decreased the V max of microsomal TTPase by about one‐half, increased that of TDPase about 3‐fold, and lowered the K m value for TDP but not for TTP. Acetone treatment of the microsomal fraction lowered the TTPase activity and markedly enhanced the TDPase activity. In acetone‐treated microsomes, chlorpromazine also inhibited TTPase activity but did not activate TDPase. Deoxycholate had similar effects to chlorpromazine on these enzyme activities.