2-Amino-6-methyl-5,6,7,8-tetrahydro-4(3H)-pteridinone 20096-90-6 4(1H)-Pteridinone, 2-amino-5,6,7,8-tetrahydro-6-methyl- 6-Methyl-5,6,7,8-tetrahydrobiopterin 6-Methyl-5,6,7,8-tetrahydropteridine 6-Methyltetrahydropteridine 6-Mph4 6-methyltetrahydropterin 942-41-6 MPH4 Tyrosine hydroxylase pteridine cofactor