title: Biopterin. VI. Purification and primary amino acid sequence of mammalian D-erythro-7,8-dihydroneopterin triphosphate synthetase.
abstract: An enzyme that catalyzes the conversion of 2-amino-6-(5'-triphosphoribosyl)amino-5- or 6-formamido-6-hydroxypyrimidine, but not of guanosine triphosphate, to quinonoid 6-(D-erythro-1'-2'-3'-trihydroxypropyl)dihydropterin triphosphate and formic acid has been purified to homogeneity from some mammalian brain and liver. The enzyme of a single strand is a basic protein of 9177 daltons consisting of 68 amino acid residues--except the enzyme from rat brain, which has one additional aspartic acid as residue 7. The enzyme possesses three free SH groups and, in its most active form, 1 mol of phosphate per mole of enzyme. Peptides isolated after hydrolysis with trypsin, chymotrypsin, or weak acid were separated by thin-layer chromatography and sequenced manually by Edman degradation. The complete sequence of the molecule was established as follows: (formula: see text)
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001708:Biopterins / Q000096:biosynthesis* / Q000378:metabolism; D001921:Brain / Q000201:enzymology; D002417:Cattle; D002645:Chickens; D006168:Guinea Pigs; D008970:Molecular Weight; D011621:Pteridines / Q000096:biosynthesis*; D011817:Rabbits; D051381:Rats; D013438:Sulfhydryl Compounds / Q000032:analysis
chemical_list: D011621:Pteridines; D013438:Sulfhydryl Compounds; D001708:Biopterins