Shen R S
Biochim Biophys Acta. 1984 Mar 29;785(3):181-5. doi: 10.1016/0167-4838(84)90142-0.
L-Phenylalanine and its metabolites, such as phenylpyruvate, phenylacetate and L-phenyllactate, do not significantly inhibit dihydropteridine reductase purified from human and sheep liver (I50 greater than or equal to 5 mM). However, L-tyrosine and its metabolites, such as L-DOPA, tyramine, p-hydroxyphenylpyruvate, p-hydroxyphenylacetate, and p-hydroxyphenylacetate, are potent noncompetitive inhibitors of this enzyme, with Ki values in the range 4-260 microM. These results suggest that tyrosine metabolites can potentially regulate levels of tetrahydrobiopterin, the required cofactor for the hydroxylation of aromatic amino acids.
L-苯丙氨酸及其代谢产物，如苯丙酮酸、苯乙酸和L-苯乳酸，不会显著抑制从人和羊肝脏中纯化的二氢蝶啶还原酶（半数抑制浓度大于或等于5 mM）。然而，L-酪氨酸及其代谢产物，如L-多巴、酪胺、对羟基苯丙酮酸、对羟基苯乙酸和对羟基苯乳酸，是该酶的强效非竞争性抑制剂，其抑制常数（Ki）值在4-260微摩尔范围内。这些结果表明，酪氨酸代谢产物可能潜在地调节四氢生物蝶呤的水平，而四氢生物蝶呤是芳香族氨基酸羟基化所需的辅助因子。
