• Applied Microscopy
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• v.27 no.4
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• pp.461-472
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• 1997

The substantia nigra of the Mongolian gerbil was studies by tyrosine hydroxylase immunohistochemistry and immunoelectron microscopy with preembedding method. The purpose was to obtain information on the distribution and ultrastructure of the Tyrosine hydroxylase immunoreactive and dopaminergic neurons in the substantia nigra, in order to provide the necessary background for the gerbil. Large number of tyrosine hydroxylase immunoreactive neurons were located in the compact part of substantia nigra. Findings in the gerbil, compared to observations in the other species, included the presence of prominent bundles of tyrosine hydroxylase immunoreactive cytoplasmic processes passing in the dorsoventral direction from pars compacta into pars reticulata at middle and caudal levels of the substantia nigra, and the presence of a distinct tyrosine hydroxylase immunoreactive substantia nigra pars lateralis. Tyrosine hydroxylase immunoreactive neurons had well-developed cell organelles, especially rough endoplasmic reticulum, free ribosome and poly-ribosome, and showed the infoldings of the nuclear envelope. We anticipate that the present description of the cellular organization of the tyrosine hydroxylase immunoreactive dopaminergic area in the substantia nigra of gerbil will be useful for the animal experimental model of Parkinson's disease.

• Journal of Plant Biology
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• v.35 no.3
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• pp.191-195
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• 1992

Changes in activity of gibberellin C20-hydroxylase which converts $[^{14}C]GA_{12}\;to\;GA_{l5}$ were studied during seed maturation using the partially purified enzyme preparations of two cultivars, Kentucky Wonder (normal) and Masterpiece (dwarf) of Phaseolus vulgaris. The preparations obtained by methanol precipitation and hydrophobic interaction chromatography efficiently converted; $GA_{l2}\;to\;GA_{4},\;via\;GA_{15},\;GA_{24}\;and\;GA_{9};\;GA_{20}\;to\;GA_{1},\;GA_{5}\;and\;GA_{6}$. The activities of C20-hydroxylase which converts $GA_{l2}\;to\;GA_{l5}$ were almost the same in both cultivars. The C20-hydroxylase activity per protein reached a maximum at the very early immature seed stage, followed by a subsequent rapid decrease during seed maturation, whereas the enzyme specific activity per seed reached a maximum at 21 days after flowering, and showed a similar fiuctuation to that of the 313-hydroxylase which converts $GA_{20}\;to\;GA_{l}$ during seed maturation.ration.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.501-507
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• 1997

Chloroplasts isolated from Stevia rebaudiana Bertoni leaves contained an enzyme activity which catalyzed hydroxylation of ent-kaurenoic acid (ent-kaur-16-en-19-oic acid; ent-KA) to steviol (ent-13-hydroxy kaur-16-en-19-oic acid), the diterpenoid carboxylic alcohol which is the aglycone of sweet stevioside-related glycosides. $[^(14)C]-methylated$ ent-KA was used to localize ent-KA hydroxylase. $[^(14)C]-methyl-KA$ was most actively was transformed into methyl-steviol in chloroplast. The enzymatic activity was found in stroma fraction but not in thylakoid membrane in Stevia rebaudiana Bertoni. However, ent-KA 13-hydroxylase activity was not detected in stroma fraction of either Spinacia oleracea and Solidago altissima. The reaction products using $[^(14)C]-methyl-KA$ were purified and identified on TLC autoradiogram. The hydroxylation of ent-KA from stromal protein to form steviol required NADPH and oxygen. FAD and riboflavin stimulated the enzyme activity 1.5-and 1.7-fold, respectively. It also turned out that the activity of this enzyme using methyl-KA as a substrate was 16.7% that of ent-KA. The purified ent-KA 13-hydroxylase did not act on t-cinnamic acid, 4-hydroxyphenyl acetic acid, choline and resorcinol, known as monooxygenase and hydroxylase substrates.

• Journal of Plant Biology
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• v.35 no.3
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• pp.185-190
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• 1992

Changes in activity of gibberellin $3{\beta}-hydroxylase$ which converts $[^3H]GA_{20}\;to\;GA_1$ were studied during seed maturation using partially purified enzyme preparations of two cultivars, Kentucky Wonder (normal) and Masterpiece (dwarf) of Phaseolus vulgaris. The specific activity of $3{\beta}-hydroxylase$ per seed reached maximum at 21 days after flowering and subsequently decreased during seed maturation in both cultivars. The ratios of conversion of $[17-^{13}C,\;^3H_2]GA_{20}\;to\;GA_1.\;GA_5,\;and\;GA_6$ by the same amount of $3{\beta}-hydroxylase$ were almost identical. Epoxidation of $GA_5\;to\;GA_6$ is also catalyzed by the partially purified $3{\beta}-hydroxylase$ preparation(Kobayashi et aI., 1991) and the conversion was inhibited by the substrates of $3{\beta}-hydroxylase$. These results suggest that the same enzyme might catalyze $3{\beta}-hydroxylase{\;}of{\;}GA_{20}\;to\;GA_1$ and epoxidation of $GA_5\;to\;GA_6$..

• Clinical and Experimental Pediatrics
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• v.54 no.2
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• pp.51-54
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• 2011

Vitamin D is present in two forms, ergocalciferol (vitamin $D_2$) produced by plants and cholecalciferol (vitamin $D_3$) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 $[1,25(OH)_2D]$, plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of $1,25(OH)_2D$ from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the $1{\alpha}$-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D $1{\alpha}$-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of $1,25(OH)_2D$ despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human $1{\alpha}$-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and $1{\alpha}$-hydroxylase mutations with clinical findings.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.323-327
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• 1998

The flavonoid biosynthetic pathway has been studied as a genetic model system, particularly in Petunia hybrida. In order to study the flavonoid biosynthetic pathway, we constructed a fusion gene system between Cauliflower Mosaic Virus (CaMV) 35S promoter and eggplant flavonoid 3', 5'-hydroxylase in pBI 121 plasmid. An optimal condition for plant regeneration was observed when internode explants were cultured on MS medium supplemented with IAA 0.2 mg/L plus BA 3 mg/L. For plant transformation internode explants of Petunia hybrida were precultured on BM medium supplemented with IAA 0.2 mg/L plus BA 3 mg/L. Putative transgenic plants were selected on medium containing kanamycin 50 mg/L plus cefotaxim 300 mg/L. Putative selected transformants were confirmed by amplification of selectable marker gene (nptII) by polymerase chain reaction (PCR) and Southern hybridization of flavonoid 3',5'-hydroxylase gene.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.366-372
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• 1989

Twenty-one strains were tested for 11$\beta$-hydroxylation of Reichstein's substance S. Four fungi exhibited ability for the reaction, among which Pellicularia fillamentosa showed the highest activity. The 11$\beta$-hydroxylase of this fungus was proved to be induced by the substrate, cycloheximide reducing significantly the activity of the enzyme. Range of optimum pH for the 11$\beta$-hydroxylation was broad and found to be 2.0-8.0. Test of the enzyme activity at different growing stages, from spore to mycelia, showed that the branching stage of hyphae and the mature mycelial stage were the most effective for the Reichstein's substance S transformation. However, 11$\beta$-hydroxylase in the intact spore was turned out to be uninducible with the substrate.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.295-299
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• 1998

Oligonucleotide primers were designed and successfully applied to amplify DNA fragments of P450 hydroxylase genes from actinomycetes which produce a large variety of medically important metabolites. Primers were designed based on several regions of strong similarities in amino acid sequence of P450 hydroxylases from a variety of actinomycetes, primarily in the regions of an oxygen binding site and a heme ligand pocket. These primers were used to amplify DNA fragments from seven different actinomycetes species producing a variety of different compounds. The deduced amino acid sequences of the isolated fragments revealed significant similarities to known P450 hydroxylase including the product of the suaC or subC genes from Streptomyces griseolus that is capable of metabolizing a number of sulfonylurea herbicides, and to the product of the $P450_{sca2}$ from S. carbophilus that produces a specific HMG-CoA reductase inhibitor. This method should help researchers in cloning the P450 hydroxylase genes involved in the biosynthesis of useful compounds.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.422-429
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• 2008

In this work, we analyzed the activity of control enzymes of flower color biosynthesis, chalcone synthase (CHS) and flavanone 3-hydroxylase (FHT) using biochemical and enzymological methods in Lilium longiflorum and 11 Lilium cultivars. The results obtained are as follows ; Naringenin (NAR) was synthesized in all Lilium cultivars tested by the catalytic activity of CHS which used malonyl-CoA and 4-coumaryol-CoA as substrates. Substrate-specific activity of CHS was observed because eridictiol (ERI), which uses caffeoyl-CoA as a substrate, was not detected in tested cultivars. In next step, dihydroflavone product was synthesized by FHT using flavanones as a substrate. FHT synthesized dihydrokaempferol (DHK) by using NAR as substrates. A remarkable activity of FHT was observed in other 11 cultivars.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.85-85
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• 2002

As an effort to direct differentiation of human embryonic stem cells (hES, MB03) to dopamine-producing neuronal cells, we expressed Nurr-l in hES and examined the expression of tyrosine hydroxylase (TH) after bFGF induction. To introduce Nurr-l, hES cells were maintained in humidified chamber with 5% CO₂ and 95% air in DMEM/Fl2 supplemented with FBS (10%), penicillin (100U/㎖), and streptomycin (100㎍/㎖). (omitted)