Induction of Phenylalanine Deaminase by Light and its Relation to Chlorogenic Acid Synthesis in Potato Tuber Tissue

Zucker, Milton

doi:10.1104/pp.40.5.779

Cited by 538 publications

(229 citation statements)

References 17 publications

Supporting

Mentioning

207

Contrasting

Unclassified

Order By: Relevance

“…A atividade expressa em unidade por minuto por grama de tecido fresco (U min -1 g -1 ), segundo o método de Teisson (1979); h) fenilalanina amônia-liase (PAL): foi realizada com base na técnica preconizada por Rhodes & Wooltorton (1971). A atividade enzimática foi expressa em U min -1 g -1 , definida como conteúdo de enzima que produz um aumento na absorbância a 290 nm de 0,01 por minuto (Zucker, 1965); I) polifenoloxidase (PPO): a extração e determinação da atividade da PPO foram realizadas de acordo com o método proposto por Matsumo & Uritane (1972). A atividade expressa em unidade por minuto por grama de tecido fresco (U min -1 g -1 ), segundo o método de Teisson (1979); j) taxa respiratória: foi determinada utilizando recipientes de vidro os quais foram fechados por 1 hora, com tampa plástica, contendo septo de silicone, por onde foram retiradas alíquotas da atmosfera interna, com auxílio do analisador de gases PBI Dansensor.…”

Section: Methodsunclassified

Efeito de diferentes temperaturas na qualidade de mandioquinha-salsa minimamente processada

Nunes¹,

Boas

Píccoli

et al. 2010

Hortic. Bras.

View full text Add to dashboard Cite

A mandioquinha-salsa é uma planta eudicotiledônea, da ordem Umbellales, família Apiaceae (Umbelliferae), gênero Arracacia, espécie Arracacia xanthorrhiza Bancroft. A família das apiáceas compreende também a cenoura, a salsa, o coentro, o aipo e o funcho, entre outras.De acordo com Pereira (1997), a mandioquinha-salsa caracteriza-se como alimento essencialmente energético, destacando-se os teores de carboidratos em relação aos demais nutrientes. Dos carboidratos totais, cerca de 80% correspondem ao amido e 6% aos açúcares totais. O amido de mandioquinha-salsa contém baixos teores de amilopectina e ausência total de fatores anti-nutricionais, conferindolhe alta digestibilidade. As proteínas são incompletas, como ocorre em outras NUNES EE; VILAS BOAS EVB; PICCOLI RH; XISTO ALRP; VILAS BOAS BM. 2010. Efeito de diferentes temperaturas na qualidade de mandioquinhasalsa minimamente processada. RESUMOO objetivo do presente trabalho foi avaliar a vida útil de mandioquinha-salsa 'Amarela de Senador Amaral' minimamente processada e armazenada em três temperaturas de armazenamento. As raízes foram descascadas manualmente, fatiadas (±1 cm de espessura), imersas em solução de dicloro isocianurato de sódio 100 mg L -1 por 15 minutos e acondicionadas em embalagem rígida de polipropileno (15 x 11,5 x 4,5 cm). As embalagens, contendo cerca de 150 g de raízes minimamente processadas, foram armazenadas a 0±1ºC, 5±1ºC ou 10±1ºC durante 15 dias, sendo realizadas análises a cada 3 dias. O delineamento experimental foi inteiramente casualizado em fatorial 3 x 6, sendo 3 temperaturas de armazenamento e 6 períodos de armazenamento, com 3 repetições. O armazenamento a 0ºC determinou, ao longo do armazenamento, aumento nos valores de L* e b*, menores valores de a*, menor atividade da peroxidase, polifenoloxidase, poligalacturonase, solubilização péctica e taxa respiratória, sendo a temperatura mais indicada para o armazenamento da mandioquinha-salsa 'Amarela de Senador Amaral' minimamente processada. Palavras-chave:Arracacia xanthorrhiza, processamento mínimo, peroxidase, polifenoloxidase. ABSTRACT Effect of different temperatures on the quality of fresh-cut Peruvian carrotThe shelf life of fresh-cut Peruvian carrots 'Amarela de Senador Amaral', stored under three temperatures, was evaluated. The roots were peeled manually, sliced (±1 cm thick), immersed in a solution of sodium dichloroisocyanurate 100 mg L -1 during 15 minutes and packed in rigid polypropylene package (15 x 11.5 x 4.5 cm). The packages containing around 150 g of fresh cut roots were stored under 0±1ºC, 5±1ºC or 10±1ºC during 15 days. The analyses were performed every 3 days. The experimental design was completely randomized in a 3 x 6 factorial (3 storage temperature) and 6 periods of storage, with three replicates. The storage at 0ºC provided higher L* and b* values, lower a* values, lower peroxidase, polyphenoloxidase and polygalacturonase activity, pectic solubilization and respiration rate. This temperature is the most proper for the storage of the fresh-cut peruvian...

show abstract

Section: Methodsunclassified

Efeito de diferentes temperaturas na qualidade de mandioquinha-salsa minimamente processada

Nunes¹,

Boas

Píccoli

et al. 2010

Hortic. Bras.

View full text Add to dashboard Cite

show abstract

“…Phenylalanine ammonia-lyase, first described in plant tissue by Koukol and Conn (9), has received much attention during the last decade mainly because of its strategic position in the biosynthetic pathway of polyphenols and lignin (10) and because of the strong effect light has on its synthesis (3,17). Physiological interest in this enzyme led to the development of rapid methods for determination of PAL2 activity.…”

Section: Methodsmentioning

confidence: 99%

“…Physiological interest in this enzyme led to the development of rapid methods for determination of PAL2 activity. The method used by Zucker (17) of determining the absorption of the trans-cinnamate formed at 290 nm in the reaction mixture has been followed in most cases (2,11,15). His reaction mixture consisted of borate buffer pH 8.8, L-phenylalanine, and enzyme extract.…”

Section: Methodsmentioning

confidence: 99%

Possible Errors in Quantitative Determination of Phenylalanine Ammonia-Lyase Activity by Spectrophotometric Methods

Erez¹

1973

Plant Physiol.

View full text Add to dashboard Cite

A possible error in spectrophotometric determination of cinnamate, the product of phenylalanine ammonia-lyase activity, using nonpurified protein extracts has been shown.Under optimal conditions for phenylalanine ammonia-lyase activity, with borate buffer and in the presence of ao-keto acids, phenylpyruvate is produced and its enol tautomer-borate complex formed, strongly absorbs at 290 nanometers.idoxal phosphate to the reaction system (4) was not confirmed for phenylalanine (5) or the related tryptophan (14) transaminases. PLP will interfere in,the estimation of trans-cinnamate at 290 nm only under conditions that will drive the keto-enol equilibrium of PLP towards the enol tautomer. This will happen under acidic conditions, under very basic conditions (12), or in the presence of borate (8). The complex enol-borate formed absorbs strongly at 290 nm with X maximum at 298 nm. The possible interference between the two enzymes has therefore been investigated in crude extracts of peach apices in borate buffer, pH 8.8. MATERIALS AND METHODSPhenylalanine ammonia-lyase, first described in plant tissue by Koukol and Conn (9), has received much attention during the last decade mainly because of its strategic position in the biosynthetic pathway of polyphenols and lignin (10) and because of the strong effect light has on its synthesis (3,17). Physiological interest in this enzyme led to the development of rapid methods for determination of PAL2 activity. The method used by Zucker (17) of determining the absorption of the trans-cinnamate formed at 290 nm in the reaction mixture has been followed in most cases (2,11,15). His reaction mixture consisted of borate buffer pH 8.8, L-phenylalanine, and enzyme extract. The wavelength of 290 nm was chosen in order to avoid the absorption of phenylalanine that interferes with X maximum of cinnamate at 268 nm (17). In later work Zucker replaced the acetone powder preparation by direct aqueous extract because of the rapidity of this procedure, as well as the decrease in variation between samples as compared with the acetone powder method (18,19). In crude aqueous extracts, it may be expected that a-keto acids will be present, thus furthering the activity of PT in the reaction mixture determining PAL. Purifying crude extracts with active carbon (11) did not remove a-keto acids from the enzyme preparation. In these cases PLP and an amino acid corresponding to the keto acid present will be produced. PT is widespread in plants (5, 6, 10). Its pH optimum is 8.0. Furthermore, PT has a rather broad substrate specificity for the keto acid-amino group receptor, and it transaminates phenylalanine with a-KG, pyruvate, and oxaloacetate (4, 5). The Two-year-old plants of the peach cultivar Redhaven, grown in 15-liter containers outdoors, were used. Apices consisting of the meristem and the three youngest leaves were taken for enzymic analyses.Enzymic extract has been prepared essentially according to Wightman and Cohen (16) in phosphate buffer, pH 8.5. The grinding medium included 10 mm...

show abstract

“…It inhibits the induction of flowering in Xanthium (5) and Lemna (20) and auxin-stimulated cell elongation in the Avena coleoptile (14). Synthesis of enzymes such as a-amylase in barley (21), invertase in yeast (6), and phenylalanine ammonia lyase in potato disks (23) are also inhibited by ethionine. To our knowledge, all processes which are inhibited by ethionine are reversed by the addition of methionine to the plant.…”

mentioning

confidence: 99%

Effect of Ethionine on Invertase Development and Methylation of Ribonucleic Acid

1970

View full text Add to dashboard Cite

Ethionine, an analogue of methionine, has been used as an antimetabolite in animals and plants. It inhibits the induction of flowering in Xanthium (5) and Lemna (20) and auxin-stimulated cell elongation in the Avena coleoptile (14). Synthesis of enzymes such as a-amylase in barley (21), invertase in yeast (6), and phenylalanine ammonia lyase in potato disks (23) are also inhibited by ethionine. To our knowledge, all processes which are inhibited by ethionine are reversed by the addition of methionine to the plant.The development of invertase in the sugar beet disk was studied according to the methods used by Cherry (3). The aeration of disks was carried out in sterile 50-mm plastic Petri dishes containing 1 ml of 0.01 M phosphate buffer, pH 6.5, 10-4 M penicillin, and 10-4 M streptomycin. The incubation medium was changed every 8 to 10 hr. For incorporation of labeled precursors into RNA, 10 g of sugar beet disks were incubated for 6 hr in sterile aeration buffer containing the amount of labeled precursors indicated in the results. Adenosine and guanosine, 10-4 M, were added to the incubation medium to suppress methyl group incorporation from L-(methyl-3H)-methionine into the purine ring. Total nucleic acids were extracted from the tissue by the phenoldupanol method of Cherry et al. (4) and fractionated on a Sephadex G-100 column (105 cm X 1.0 cm) by the method of Galibert et al. (10).A leucyl-tRNA synthetase preparation was extracted from sugar beet by grinding 100 g of tissue in liquid nitrogen with subsequent suspension of the powdered material in 100 ml of a solution containing 0.1 M tris-HCl, pH 7.8; 0.04 M KCI; 0.04 M MgCl2; 0.01 M 2-mercaptoethanol; 0.2 M ascorbate; and 1.0 M sucrose. Following cheesecloth filtration and centrifugation at 15,000g for 15 min, the supernatant was brought to 70% saturation with respect to ammonium sulfate. The protein precipitate was dissolved in, and dialyzed overnight against, a solution containing 0.05 M tris-HCl, pH 7.8; 0.02 M KCI; 0.02 M MgCl2; and 0.005 M 2-mercaptoethanol. Subsequently, the protein concentration of the preparation was adjusted to 1 to 2 mg/ml for the aminoacylation assay.Soluble RNA was isolated by the method of Anderson and Cherry (1), except that the RNA was solubilized in 2 M potassium acetate, pH 6.5, instead of in 1 M sodium chloride. Leucine acceptor activity was assayed by the method of Anderson and Cherry (1).Invertase activity in the beet disks increased linearly over a 72-hr incubation period (Fig. 1) (3) with actinomycin D and suggest that ethionine affects some early stages of invertase development.The observed inhibition of invertase by ethionine may be due to the substitution of ethionine for methionine during invertase synthesis, resulting in altered biological activity or reduced rate of synthesis, or both. Yoshida and Yamosaki (22) reported that one-third of the methionine in a-amylase from Bacillus subtilis was substituted by ethionine without alteration of the physiochemical and biological properties of the isolated enzyme. During...

show abstract

Induction of Phenylalanine Deaminase by Light and its Relation to Chlorogenic Acid Synthesis in Potato Tuber Tissue

Cited by 538 publications

References 17 publications

Efeito de diferentes temperaturas na qualidade de mandioquinha-salsa minimamente processada

Efeito de diferentes temperaturas na qualidade de mandioquinha-salsa minimamente processada

Possible Errors in Quantitative Determination of Phenylalanine Ammonia-Lyase Activity by Spectrophotometric Methods

Effect of Ethionine on Invertase Development and Methylation of Ribonucleic Acid

Contact Info

Product

Resources

About