The enzyme that synthesizes tetrahydrobiopterin from 6-pyruvoyl-tetrahydropterin in the lemon mutant silkworm consists of two carbonyl reductases

Archives of Biochemistry and Biophysics
T IinoH Sawada


Tetrahydrobiopterin plays an important role in the biosynthesis of certain neurotransmitters. Using DEAE-Sepharose FF column chromatography, we separated the enzyme that synthesizes tetrahydrobiopterin from 6-pyruvoyl-tetrahydropterin [which is different from sepiapterin reductase (EC] in the lemon mutant of the silkworm Bombyx mori into two fractions, which were named carbonyl reductase I (CR I) and carbonyl reductase II (CR II). The CR I enzyme converted 6-pyruvoyl-tetrahydropterin to 6-lactoyl-tetrahydropterin, while CR II converted 6-pyruvoyl-tetrahydropterin to 1'-hydroxy-2'-oxopropyl-tetrahydropterin, both reactions occurring only in the presence of NADPH. Neither of the two carbonyl reductases alone was able to catalyze the conversion of 6-pyruvoyl-tetrahydropterin to tetrahydrobiopterin in the presence of NADPH. However, when CR I was mixed with CR II in the reaction mixture, 6-pyruvoyl-tetrahydropterin was reduced to tetrahydrobiopterin in the presence of NADPH. Moreover, CR I catalyzed the formation of tetrahydrobiopterin from 1'-hydroxy-2'-oxopropyl-tetrahydropterin, while CR II converted 6-lactoyl-tetrahydropterin to tetrahydrobiopterin, both reactions occurring only in the presence of NADPH. Our results ...Continue Reading


Mar 29, 1991·Biochemical and Biophysical Research Communications·Y S ParkN Blau
Nov 15, 1989·Biochemical and Biophysical Research Communications·P SteinerstauchH C Curtius
Jan 1, 1988·Annual Review of Nutrition·N Blau
May 16, 1985·Biochemical and Biophysical Research Communications·S Milstien, S Kaufman
Feb 14, 1984·Biochemical and Biophysical Research Communications·S Katoh, T Sueoka
May 16, 1984·Biochemical and Biophysical Research Communications·A C SwitchenkoG M Brown
Apr 20, 1983·Biochimica Et Biophysica Acta·S I YoshiokaM Akino

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