• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.333-337
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• 1997

Trans-cinnamic acid-4-hydroxylase(tC4H) is the first cytochrome P450-dependent monooxygenase of the phenylpropanoid pathway. The roots of avocado seedlings were wounded and examined to determine whether the tC4H would be activated in response to wounding and/or whether tC4H activity be modulated by the application of exogenous p-coumarate. At the specified length of times, the wounded and treated roots were either frozen in liquid nitrogen or used immediately to extract microsomal proteins. The microsomal proteins were subjected to immunoblot analysis using polyclonal antibodies against CYP73 of tC4H gene. In this study, tC4H was induced in wounded roots sealed in bags within 6 hours, and in low level({TEX}$10^{-8}${/TEX}M) of p-coumarate solution within 24 hours, whereas the olution without p-coumarate and high levels of p-coumarate solution repressed tC4H induction in wounded roots. These results indicate that tC4H is induced by wounding in the root of avocado, and is inhibited by the application of exogenous p-coumarate.

• Korean Journal of Plant Tissue Culture
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• v.24 no.4
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• pp.233-238
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• 1997

Salicylic acid (SA) is involved in the establishment of systemic acquired resistance (SAR) in many plant including tobacco. Considering the important role of SA in disease resistance, biosynthetic and metabolic pathways of SA in tobacco have been studied extensively: The initial step for biosynthetic pathway of SA is conversion of phenylalanine to trans-cinnamic acid, followed by decarboxylation of trans-cinnamic acid to benzoic acid and ie subsequent ring hydroxylation at the C-2 position to form SA. In TMV inoculated tobacco, most of the newly synthesized SA is glucosylated or methylated. Methyl salicylate has been identified as a biologically active, volatile signal. In contrast, the two glucosylated forms accumulate in the vicinity of lesions and consist of SA glucoside, a major metabolite, and SA glucose ester, a relatively minor from. Two enzymes involved in SA biosynthesis and metabolism have been purified and characterized : benzoic acid 2-hydroxylase which catalyzes conversion of benzoic acid to SA; UDP-Glucose: SA 1-O-D glucosyltransferase which converts SA to SA glucose ester. Further studies of the biosynthetic and metabolic pathways of SA will help to elucidate the SAR signal transduction pathway and provide potential tools for the manipulation of disease resistance.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.20 no.2
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• pp.37-43
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• 2020

Phenylketonuria is the most prevalent disorder caused by an inborn error in aminoacid metabolism. It results from mutations in the phenylalanine hydroxylase (PAH) gene. If untreated or late treated, results in profound and irreversible mental disability. Newborn screening test identify patients with phenylketouria. The early initiation of a phenylalanine restricted diet very soon prevents most of the neuropsychiatric complications. However, the diet therapy is difficult to maintain and compliance is poor, especially in adolescents and adulthood. Since 2015, American Medical College of Medical Genetics and Genomics (ACMG) recommended more strong restrictive diet therapy for target blood level of phenylalanine (<360 umol/L). For over four decades the only treatment was a very restrictive low phenylalanine diet. This changed in 2007 with the approval of cofactor therapy (Tetrahydrobiopterin, BH4) which is effective in up to 30% of patients. Data from controlled clinical trials with sapropterin dihydrochloride indicate a similar occurrence of all-cause adverse events with this treatment and placebo. Large neutral aminoacids (LNAA) competes with phenylalanine for transport across the blood-brain-barrier and have a beneficial effect on executive functioning. A new therapy has just been approved that can be effective in most patients with PAH deficiency regardless of their degree of enzyme deficiency or the severity of their phenotype. Phenylalanine ammonia lyase (PAL-PEG) was approved in the USA by FDA in May of 2018 for adult patients with uncontrolled blood phenylalanine concentrations on current treatment. Nucleic acid therapy (therapeutic mRNA or gene therapy) is likely to provide longer term solutions with few side effects.