Drosophila alcohol dehydrogenase activity in vitro and in vivo: Effects of acetone feeding

1979 ◽  
Vol 17 (5-6) ◽  
pp. 553-563 ◽  
Author(s):  
Ira Papel ◽  
Melford Henderson ◽  
Jeanine Van Herrewege ◽  
Jean David ◽  
William Sofer
1976 ◽  
Vol 54 (6) ◽  
pp. 539-545 ◽  
Author(s):  
G. W. Forsyth ◽  
H. T. Nagasawa ◽  
C. S. Alexander

Rat hearts perfused with oxygenated buffer containing [1-14C]ethanol metabolized small amounts of the ethanol to carbon dioxide. Very sensitive techniques are required to separate the resulting 14CO2 from the ethanol. This metabolism is not inhibited by levels of pyrazole which markedly inhibit NAD dependent liver alcohol dehydrogenase (EC 1.1.1.1). In vitro studies suggest that NADP functions as a cofactor for the rat heart alcohol dehydrogenase activity of crude heart homogenates. The kinetic parameters, the specific activity, and the pH dependence of the enzyme activity measured in these experiments suggest that it may have a minor role in ethanol metabolism by the rat.


2002 ◽  
Vol 363 (3) ◽  
pp. 769-776 ◽  
Author(s):  
Tobias MODIG ◽  
Gunnar LIDÉN ◽  
Mohammad J. TAHERZADEH

The kinetics of furfural inhibition of the enzymes alcohol dehydrogenase (ADH; EC 1.1.1.1), aldehyde dehydrogenase (AlDH; EC 1.2.1.5) and the pyruvate dehydrogenase (PDH) complex were studied in vitro. At a concentration of less than 2mM furfural was found to decrease the activity of both PDH and AlDH by more than 90%, whereas the ADH activity decreased by less than 20% at the same concentration. Furfural inhibition of ADH and AlDH activities could be described well by a competitive inhibition model, whereas the inhibition of PDH was best described as non-competitive. The estimated Km value of AlDH for furfural was found to be about 5μM, which was lower than that for acetaldehyde (10μM). For ADH, however, the estimated Km value for furfural (1.2mM) was higher than that for acetaldehyde (0.4mM). The inhibition of the three enzymes by 5-hydroxymethylfurfural (HMF) was also measured. The inhibition caused by HMF of ADH was very similar to that caused by furfural. However, HMF did not inhibit either AlDH or PDH as severely as furfural. The inhibition effects on the three enzymes could well explain previously reported in vivo effects caused by furfural and HMF on the overall metabolism of Saccharomyces cerevisiae, suggesting a critical role of these enzymes in the observed inhibition.


1980 ◽  
Vol 186 (2) ◽  
pp. 483-490 ◽  
Author(s):  
Gloria Rachamin ◽  
J. Alain Macdonald ◽  
Samina Wahid ◽  
Jeremy J. Clapp ◽  
Jatinder M. Khanna ◽  
...  

In young (4-week-old) male and female spontaneously hypertensive (SH) rats, ethanol metabolic rate in vivo and hepatic alcohol dehydrogenase activity in vitro are high and not different in the two sexes. In males, ethanol metabolic rate falls markedly between 4 and 10 weeks of age, which coincides with the time of development of sexual maturity in the rat. Alcohol dehydrogenase activity is also markedly diminished in the male SH rat and correlates well with the changes in ethanol metabolism. There is virtually no influence of age on ethanol metabolic rate and alcohol dehydrogenase activity in the female SH rat. Castration of male SH rats prevents the marked decrease in ethanol metabolic rate and alcohol dehydrogenase activity, whereas ovariectomy has no effect on these parameters in female SH rats. Chronic administration of testosterone to castrated male SH rats and to female SH rats decreases ethanol metabolic rate and alcohol dehydrogenase activity to values similar to those found in mature males. Chronic administration of oestradiol-17β to male SH rats results in marked stimulation of ethanol metabolic rate and alcohol dehydrogenase activity to values similar to those found in female SH rats. Chronic administration of ethanol to male SH rats from 4 to 11 weeks of age prevents the marked age-dependent decreases in ethanol metabolic rate and alcohol dehydrogenase activity, but has virtually no effect in castrated rats. In the intoxicated chronically ethanol-fed male SH rats, serum testosterone concentrations are significantly depressed. In vitro, testosterone has no effect on hepatic alcohol dehydrogenase activity of young male and female SH rats. In conclusion, in the male SH rat, ethanol metabolic rate appears to be limited by alcohol dehydrogenase activity and is modulated by testosterone. Testosterone has an inhibitory effect and oestradiol has a testosterone-dependent stimulatory effect on alcohol dehydrogenase activity and ethanol metabolic rate in these animals.


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