ISSN:
1432-2048
Keywords:
Datura (root, alkaloid)
;
Enzyme inhibition
;
Root culture (alkaloid production)
;
8-Thiabicyclo[3.2.1]octan-3-one
;
8-Thiabicyclo[3.2.1]octan-3-ol
;
Tropane alkaloid biosynthesis
;
Tropinone reductase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The nortropane sulphur analogues 8-thiabicyclo[3.2.1] octan-3-one, 8-thiabicyclo[3.2.1]octan-3a-ol and 8-thiabicyclo[3.2.1]octan-3β-ol have been found to have differential effects in vitro on the activities of tropinone reductase I and tropinone reductase II from Datura stramonium L. It has been demonstrated that only tropinone reductase I is able to metabolise 8-thiabicyclo[3.2.1]octan-3-one and that only this enzyme is inhibited by 8-thiabicyclo[3.2.1]octan-3α-ol and 8-thiabicyclo[3.2.1]octan-3β-ol. A K m of 0.035 mM was determined for 8-thiabicyclo[3.2.1]octan-3-one and I50 values of 0.081 mM and 0.021 mM for 8-thiabicyclo[3.2.1]octan-3α-ol and 8-thiabicyclo[3.2.1]octan-3β-ol, respectively. The influence that these differential interactions might have on metabolism was investigated in transformed root cultures of D. stramonium. It was found that when these cultures were grown in the presence of either 8-thiabicyclo[3.2.1]octan-3-one or 8-thiabicyclo[3.2.1]octan-3β-ol the spectrum of alkaloids that accumulated was altered from that found in control roots in the manner predicted from the observed effects of these inhibitors on the isolated reductases. The effect could be mimicked by feeding pseudotropine, the product of tropinone reductase II. It is concluded that the relative levels of activity of the two tropinone reductases might play an important role in regulating the balance of tropan-3α-ols to tropan-3β-ols seen in the spectrum of tropane-alkaloid-producing plants.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00197052
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