Properties of phenylalanine ammonia-lyase from marrow cotyledons

El-Shora, Hamed M.

doi:10.1016/s0168-9452(01)00471-x

Cited by 36 publications

(20 citation statements)

References 38 publications

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“…PAL enzyme derived from C. fruticulosa had an optimum buff er concentration of 100 mM Tris-HCl ((54.9±0.1) U/mg) (Fig. 1c), which is similar to what has been reported for other plant PAL enzymes, including those of Cucurbita pepo (9), Medicago sativa (21) and Glycine max (29).…”

Section: Resultssupporting

confidence: 81%

“…Above optimal concentrations, NaCl may give rise to hysteresis followed by reduction of the enzymatic activity. Shielding of negatively charged amino acid residues and increasing hydrophobic interactions within the protein molecule are responsible for the stability of proteins (9). Thus, various NaCl concentrations were studied for their impact on PAL activity of C. fruticulosa at a pH=8.8 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Plants possess PAL activity that is regulated by a variety of PAL-encoding genes which may be uniquely encoded only in some regions of plants or under certain environmental conditions (9). It has formerly been shown that various plants contain PAL enzymes with a heterotetramer structure (42).…”

Section: Resultsmentioning

confidence: 99%

“…The PAL activity was determined in the presence of diff erent concentrations (50-300 mM) of NaCl (Sigma-Al-drich, Hunterdon, NJ, USA) in the reaction mixture (9). Assays were performed at 37 °C and pH=8.8 for 30 min using 100 mM Tris-HCl buff er and 40 mM l-phenylalanine.…”

Section: Determination Of Pal Specifi C Activity Under Diff Erent Nacmentioning

confidence: 99%

“…Although certain fungi and higher plants possess PAL activity, no animal has been shown to have this enzyme yet (8). Being one of several commercially available non-hydrolytic enzymes, plant PAL has been successfully utilized to treat certain neoplasms in mice as well as to measure serum levels of Phe in humans with PKU and diets low in Phe (9). Modest reductions in Phe levels have been att ained in early trials of oral administration of PAL to humans.…”

Section: Introductionmentioning

confidence: 99%

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Biochemical Evaluation of Phenylalanine Ammonia Lyase (PAL) from Endemic Cyathobasis fruticulosa (Bunge) Aellen. for the Dietary Treatment of Phenylketonuria (PKU)

Şirin¹,

Aydaş²,

Aslım³

2016

Food Technol. Biotechnol.

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SummaryEnzyme substitution therapy with the phenylalanine ammonia lyase (PAL) is a new approach to the treatment of patients with phenylketonuria (PKU). This enzyme is responsible for the conversion of phenylalanine to trans-cinnamic acid. We assessed the PAL enzyme of the endemic plant Cyathobasis fruticulosa (Bunge) Aellen. for its possible role in the dietary treatment of PKU. The enzyme was found to have a high activity of (64.9±0.1) U/ mg, with the optimum pH, temperature and buff er (Tris-HCl and l-phenylalanine) concentration levels of pH=8.8, 37 °C and 100 mM, respectively. Optimum enzyme activity was achieved at pH=4.0 and 7.5, corresponding to pH levels of gastric and intestinal juice, and NaCl concentration of 200 mM. The purifi cation of the enzyme by 1.87-fold yielded an activity of 98.6 U/mg. PAL activities determined by HPLC analyses before and aft er purification were similar. Two protein bands, one at 70 and the other at 23 kDa, were determined by Western blot analysis of the enzyme. This enzyme is a potential candidate for serial production of dietary food and biotechnological products.

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Section: Resultssupporting

confidence: 81%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Determination Of Pal Specifi C Activity Under Diff Erent Nacmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Biochemical Evaluation of Phenylalanine Ammonia Lyase (PAL) from Endemic Cyathobasis fruticulosa (Bunge) Aellen. for the Dietary Treatment of Phenylketonuria (PKU)

Şirin¹,

Aydaş²,

Aslım³

2016

Food Technol. Biotechnol.

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Essential groups and stability of α-glucosidase ofPenicillium notatum

2009

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--Glucosidase ( -D-glucoside glucohydrolase, EC 3.2.1.20) was isolated from Penicillium notatum. The enzyme was induced by gibberellic acid (GA 3 ). The GA 3 -mediated increase in the enzyme activity was repressed in presence of abscisic acid, cycloheximide and the antibiotics chloramphenicol, cordycepin, and rifampicin which are inhibitors of protein synthesis. -Glucosidase was purified 440-fold with of 27.8-fold of purification. The enzyme was immobilized using chitosan gel. The optimal pH values were 6.5 and 7.5 for free and the immobilized enzymes, respectively. The optimal temperatures were 50 and 65 °C for free and immobilized enzymes, respectively. The enzyme hydrolyzed maltose, sucrose, isomaltose, maltotriose but not starch, amylopectin and amylose. Trehalose and glycerol protected the free and immobilized enzymes against inactivation at 70 °C, however trehalose was the better protector. Phytate protected the free enzyme against heat inactivation at both 65 and 70 °C. 2,4,6 Trinitrobenzenesulfonic acid, butanedione and diethylpyrocarbonate inactivated the enzyme and suggest that, lysyl, arginyl and histidyl groups are taking part in enzyme catalysis. The inactivation by the three compounds was protected by the substrate para-nitrophenyl--D-glucopyranoside. Treatment of the enzyme with 1-ethyl-3(3-dimethyl aminopropyl)-carbodiimide, p-chloromercuribenzoate, N-bromosuccinimide, N-acetlyimidazole revealing the involving of carboxyl, sulfhydryl, trptophenyl and tyrosyl groups, respectively in the catalysis of -glucosidase. EDTA, o-phenanthroline, dipyridyl and 8-quinolinol inhibited the enzyme activity and the inhibition was higher in case of free enzyme compared with immobilized enzyme.

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Photosynthetic and biochemical mechanisms of an EMS-mutagenized cowpea associated with its resistance to cowpea severe mosaic virus

et al. 2016

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The seed treatment of a CPSMV-susceptible cowpea genotype with the mutagenic agent EMS generated mutagenized resistant plantlets that respond to the virus challenge by activating biochemical and physiological defense mechanisms. Cowpea is an important crop that makes major nutritional contributions particularly to the diet of the poor population worldwide. However, its production is low, because cowpea is naturally exposed to several abiotic and biotic stresses, including viral agents. Cowpea severe mosaic virus (CPSMV) drastically affects cowpea grain production. This study was conducted to compare photosynthetic and biochemical parameters of a CPSMV-susceptible cowpea (CE-31 genotype) and its derived ethyl methanesulfonate-mutagenized resistant plantlets, both challenged with CPSMV, to shed light on the mechanisms of virus resistance. CPSMV inoculation was done in the fully expanded secondary leaves, 15 days after planting. At 7 days post-inoculation, in vivo photosynthetic parameters were measured and leaves collected for biochemical analysis. CPSMV-inoculated mutagenized-resistant cowpea plantlets (MCPI) maintained higher photosynthesis index, chlorophyll, and carotenoid contents in relation to the susceptible (CE-31) CPSMV-inoculated cowpea (CPI). Visually, the MCPI leaves did not exhibit any viral symptoms neither the presence of the virus as examined by RT-PCR. In addition, MCPI showed higher SOD, GPOX, chitinase, and phenylalanine ammonia lyase activities, HO, phenolic contents, and cell wall lignifications, but lower CAT and APX activities in comparison to CPI. All together, these photosynthetic and biochemical changes might have contributed for the CPSMS resistance of MCPI. Contrarily, CPI plantlets showed CPSMV accumulation, severe disease symptoms, reduction in the photosynthesis-related parameters, chlorophyll, carotenoid, phenolic compound, and HO contents, in addition to increased β-1,3-glucanase, and catalase activities that might have favored viral infection.

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Properties of phenylalanine ammonia-lyase from marrow cotyledons

Cited by 36 publications

References 38 publications

Biochemical Evaluation of Phenylalanine Ammonia Lyase (PAL) from Endemic Cyathobasis fruticulosa (Bunge) Aellen. for the Dietary Treatment of Phenylketonuria (PKU)

Biochemical Evaluation of Phenylalanine Ammonia Lyase (PAL) from Endemic Cyathobasis fruticulosa (Bunge) Aellen. for the Dietary Treatment of Phenylketonuria (PKU)

Essential groups and stability of α-glucosidase ofPenicillium notatum

Photosynthetic and biochemical mechanisms of an EMS-mutagenized cowpea associated with its resistance to cowpea severe mosaic virus

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