Ozone (O3), a major photochemical oxidant, induces leaf injury concomitant with salicylic acid (SA) synthesis. In pathogen-infected leaves, SA is synthesized via two pathways, involving phenylalanine or isochorismate. SA biosynthesis under O3 fumigation is not well understood. When we applied 14C-labeled benzoic acid (a precursor of SA in the pathway via phenylalanine) to O3-exposed tobacco lea...

A cDNA clone for phenylalanine ammonia-lyase (PAL) induced in wounded sweet potato (Ipomoea batatas Lam.) root was obtained by immunoscreening a cDNA library. The protein produced in Escherichia coli cells containing the plasmid pPAL02 was indistinguishable from sweet potato PAL as judged by Ouchterlony double diffusion assays. The M(r) of its subunit was 77,000. The cells converted [(14)C]-l-p...

Plants develop a plethora of defense strategies during their acclimation and interactions with various environmental stresses. Secondary metabolites play pivotal role in the processes stress acclimation, therefore deciphering relevant responses exchange interpretation underlying molecular mechanisms that may contribute to improved adaptability efficacy. In current study, tomato plants were expo...

The aim of this study was to evaluate the physicochemical parameters mangoes for export. results revealed that lose firmness after three days storage and pulp turns yellow-orange. sugar content increases progressively along time. However, phenylalanine ammonia-lyase (PAL) activity decreases with time confirming decrease phenol content. As polyphenoloxidases (PPO) peroxidases (POD), it increased...

A separable and highly-stable enzyme system was developed by adsorption of phenylalanine ammonia lyase (PAL) from Rhodotorula glutinis in amino-functionalized macroporous silica gel and subsequent enzyme crosslinking. This resulted in the formation of cross-linked enzyme aggregates (PAL-CLEAs) into macroporous silica gel (MSG-CLEAs). The effect of adsorptive conditions, type of aggregating agen...

Both phenylalanine ammonia lyase and tyrosine ammonia lyase were detected in tobacco (Nicotiana tabacum L. Wisconsin 38) callus. The enzymes were separated from each other by Sephadex G-200 column chromatography. Increased activity of tyrosine ammonia lyase was observed during culture of tobacco callus under shoot-forming conditions, while activity of phenylalanine ammonia lyase increased durin...

The effect of ethylene on the development of phenylalanine ammonia-lyase activity in segments excised from the epicotyl apex of pea seedling was studied. Although there was some increase in phenylalanine ammonia-lyase activity in segments not treated with ethylene, a marked increase in phenylalanine ammonia-lyase activity occurred in ethylene-treated tissues during the incubation. The induction...

Fresh asparagus (Asparagus officinalis L.) deteriorates rapidly after harvest. Early enzymatic changes that follow harvesting of asparagus are important factors contributing to postharvest deterioration. We held asparagus spears at 25°C for up to 5 days after harvest and examined changes in the activities of Acid invertase (AI), Sucrose Synthase (SS), Glutamine Synthetase (GS) and Phenylalanine...

The phosphonic analogue of L-phenylalanine, (/?)-(l-am ino-2-phenylethyl)phosphonic acid (A P E P ), inhibits buckwheat phenylalanine ammonia-lyase (PAL) com petitively with a K t value o f 1.5 |iM. The K, value for the (S)-enantiomer is 11.6 jj,M. The corresponding values for the enantiom ers of the phosphonous analogue are 35 and 205 |u.m , respectively. APEP inhibits the light-induced synthe...