Comparison of the amino acid sequences of NIT4 and NIT1 homologs has permitted the identification of typical sequence motifs for NIT4 and NIT1. One of these motifs was mutated in Arabidopsis NIT4 and obtained enzymes that could convert 3-phen-ylpropionitrile three to nearly tenfold faster than the wild-type enzyme (Janowitz et al. 2009)