N-Methyl-L-phenylalanine (5), N-methyl-4-nitro-L-phenylalanine (6), and N,N-dimethyl-4-nitro-L-phenyl-alanine (7·H+) were investigated as substrates of inhibitors of phenylalanine ammonia lyase from Petroselinum crispum. Whereas the former was a reluctant substrate (K m = 6.6 mM, kcat = 0.22 s-1), no reverse reaction could be detected by using methylamine and (E)-cinnamate (2). The Km 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 (Ki = 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.
ASJC Scopus subject areas
- Drug Discovery
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry