J. Biol. Chem., Vol. 262, Issue 7, 3136-3139, 03, 1987
Peroxisomal dihydroxyacetone phosphate acyltransferase. Effect of acetaldehyde on the intact and solubilized activity
RT Dobrowsky and LM Ballas
The peroxisomal enzyme dihydroxyacetone phosphate (DHAP) acyltransferase
shows a differential response to acetaldehyde. Employing whole peroxisomes,
the enzyme displays a 130-400% stimulation of activity when assayed in the
presence of 10-250 mM acetaldehyde. Following taurocholate solubilization
of the enzyme the response to 0.25 M acetaldehyde is one of almost total
inhibition. This inhibition of the taurocholate-solubilized enzyme is not
observed at acetaldehyde concentrations below 200 mM. The stimulation of
DHAP acyltransferase by acetaldehyde is solely a response of the
peroxisomal enzyme as evidenced by its insensitivity to N-ethylmaleimide
and 5 mM glycerol 3- phosphate. Furthermore, microsomal dihydroxyacetone
phosphate acyltransferase activity is inhibited at all acetaldehyde
concentrations. The activation of membrane-bound DHAP acyltransferase by
acetaldehyde appears to be specific for this enzyme in comparison to
several other peroxisomal and microsomal enzymes. The specificity of
activation and differential response of the peroxisomal enzyme to
acetaldehyde indicates that the microenvironment of the peroxisomal
membrane is important for normal enzymatic function of this enzyme.
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