ID 4.1.2.50 DE 6-carboxytetrahydropterin synthase. AN CPH4 synthase. CA 7,8-dihydroneopterin 3'-triphosphate + H2O = 6-carboxy-5,6,7,8- CA tetrahydropterin + acetaldehyde + 2 H(+) + triphosphate. CC -!- Isolated from the bacteria Bacillus subtilis and Escherichia coli. CC -!- The reaction is part of the biosynthesis pathway of queuosine. CC -!- The enzyme from Escherichia coli can also convert 6-pyruvoyl-5,6,7,8- CC tetrahydropterin and sepiapterin to 6-carboxy-5,6,7,8- CC tetrahydropterin. DR O66626, QUED_AQUAE ; O29809, QUED_ARCFU ; O31676, QUED_BACSU ; DR Q8K9D8, QUED_BUCAP ; P65871, QUED_ECO57 ; P65870, QUED_ECOLI ; DR P44123, QUED_HAEIN ; B0R9W7, QUED_HALS3 ; Q9ZKR8, QUED_HELPJ ; DR O25587, QUED_HELPY ; Q58668, QUED_METJA ; O27296, QUED_METTH ; DR Q9UXZ4, QUED_PYRAB ; O59602, QUED_PYRHO ; Q1RHI6, QUED_RICBR ; DR Q92J44, QUED_RICCN ; Q4UKI6, QUED_RICFE ; Q9ZDY5, QUED_RICPR ; DR Q68XI9, QUED_RICTY ; P65872, QUED_SHIFL ; Q55798, QUED_SYNY3 ; //