Adaptive Use of N2-Dimethyl-Substituted Pterins by Cultures of Crithidia fasciculata1 |
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Authors: | IRMGARD ZIEGLER MANFRED B
HME WOLFGANG PFLEIDERER ERICH F ELSTNER |
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Institution: | IRMGARD ZIEGLER,MANFRED BÖHME,WOLFGANG PFLEIDERER,ERICH F. ELSTNER |
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Abstract: | The compound 6-(L-erythro-1,2′,3′-trihydroxypropyl)pterin, at a concentration of 50 pg/ml (“L-erythro-neopteria”), supports half-maximal growth of Crithidia fasciculata; biopterin at a concentration of 30 pg/ml is shown to yield similar growth. N2-dimethyl-6-(L-erythro-1′,2′,3′-trihydroxypropyl)pterin (A) was inactive even at 100 ng/ml. Synergism was observed with the N2-dimethylamino derivative (A) in the presence of suboptimal biopterin, its activity then being of the order of L-erythro-neopterin. In contrast, the stereoisomeric N2-dimethyl-6-(D-erythro-1′,2′,3′-trihydroxypropyl)pterin (“dimethyl-D-erythro-neopterin”) and its 3′-mono-phosphate only slightly enhanced growth under similar conditions but both threo-isomers had no supplementary activity. Biopterin-induced growth was slowed by 6-(D-erythro1′,2′,3′-trihydroxypropyl)pterin (D-neopterin); the threo-isomers had no such effect. An adaptive demethylation capacity by growing cultures and competition of biopterin uptake by D-neopterin seems likely. The report of the occurrence in Euglena of N2-dimethyl-6-(L-threo-1′,2′,3′-trihydroxypropyl)pterin and its 3′-mono-phosphate adds further interest to our observations. |
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