Phenylalanine aminomutases (PAMs) are 4-methylideneimidazol-5-one (MIO)-dependent enzymes that catalyze the isomerization of (S)-a-phenylalanine to give (S)or (R)-bphenylalanine, which are precursors in the biosynthesis of various natural products. Several related tyrosine aminomutases (TAMs) have also been characterized. Furthermore, the mechanistically related MIO-dependent phenylalanine, tyr...

Stored cut lettuce gradually turns brown on the cut section after several days of storage, because cutting induces phenylalanine ammonia-lyase (PAL) activity, the biosynthesis of polyphenol is promoted, and the polyphenols are oxidized by polyphenol oxidase. Here, the effect of heat shock treatment at 50 degrees C for 90 s on the quality of cut lettuce during cold storage was examined. The heat...