Kinetic and regulatory properties of phenylalanine ammonia-lyase from Citrus sinensis |
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| Institution: | 1. Department of Medicine (Division of Endocrinology, Diabetes and Metabolism) and Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, FL 32610, United States;2. Department of Health Outcomes and Policy, University of Florida, College of Medicine, Gainesville, FL 32610, United States;3. Department of Biostatistics and Neurology, Mailman School of Public Health, Columbia University, New York, NY 10032, United States;4. Department of Psychiatry (Division of Addiction Research) and Biobehavioral Core, University of Florida, College of Medicine, Gainesville, FL 32610, United States;5. Department of Medicine (Division of Endocrinology, Diabetes and Metabolism), University of Florida, College of Medicine, Gainesville, FL, United States;6. Department of Biostatistics, University of Florida, College of Medicine, Gainesville, FL 32610, United States;7. Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, United States;1. Programa Interdisciplinar em Ciências da Saúde, Universidade Federal de São Paulo, UNIFESP, Av. Ana Costa, 95, Santos, SP 11060-001, Brazil;2. Departamento de Biociências, Universidade Federal de São Paulo, UNIFESP, Rua Silva Jardim, 136, Santos, SP 11015-020, Brazil;3. Programa de Bioprodutos e Bioprocessos, Universidade Federal de São Paulo, UNIFESP, Av. Ana Costa, 95, Santos, SP 11060-001, Brazil;1. Laboratory of Laser Sports Medicine, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China;2. Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA |
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| Abstract: | - 1.1. The kinetic and regulatory properties of phenylalanine ammonia-lyase from Citrus sinensis fruit tissue were investigated. The substrate specificity of the enzyme was determined as well as the effects of pH and temperature on the catalytic activity.
- 2.2. The enzyme exhibits negative homotropic effects between the substrate binding centra.
- 3.3. Binding of l-phenylalanine to the enzyme is characterized by two Km-values; KmL = 13 μM and KmH = 52 μM; with a Hill-interaction coefficient of 0.75.
- 4.4. The enzyme is subject to product inhibition by trans-cinnamate, but the effects of allosteric effectors and inhibitors seem to be of much greater importance in the short-term regulation of phenylpropanoid metabolism in Citrus sinensis.
- 5.5. The enzyme activity was found to be modulated by end-products of diverging metabolic pathways, viz. umbelliferone, scopoletin, naringenin, quercetin, kaempferol, benzoic acid and gallic acid.
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