Mechanistic Investigation of Phenylalanine Ammonia Lyase by Using N-Methylated Phenylalanines

✍ Scribed by Sandra Viergutz; László Poppe; Anna Tomin; János Rétey

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: German
• Weight: 243 KB
• Volume: 86
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200390305

✦ Synopsis

Abstract

N‐Methyl‐L‐phenylalanine (5), N‐methyl‐4‐nitro‐L‐phenylalanine (6), and N,N‐dimethyl‐4‐nitro‐L‐phenylalanine (7⋅H^+^) were investigated as substrates or inhibitors of phenylalanine ammonia lyase from Petroselinum crispum. Whereas the former was a reluctant substrate (K~m~=6.6 mM, k~cat~=0.22 s^−1^), no reverse reaction could be detected by using methylamine and (E)‐cinnamate (2). The K~m~ value for ammonia in the reverse reaction by using (E)‐cinnamate (2) was determined to be 4.4 and 2.6M at pH 8.8 and 10, respectively. The N‐methylated 4‐nitro‐L‐phenylalanines 6 and 7 showed only strong inhibitory effects (K~i~=130 nM and 8 nM, resp.). These and former results are discussed in terms of the mechanism of action of phenyalalanine and histidine ammonia lyases.