• 미생물학회지
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• 제34권4호
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• pp.243-247
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• 1998

Allomyces macrogynus를 대상으로 꼬리홀씨와 팡이실에서 tetrahydrobiopterin의 세포내 농도와 그 생합성 효소들의 활성을 비교분석하였다. 습윤중량의 세포를 기준으로 비교하였을 때 biopterin은 홀씨에 비해 팡이실에서 14배 정도 많은 양이 검출되었다. 그 생합성에 관여하는 GTP cyclohydrolase I(GTPCH), 6-pyruboyltetrahydropterin synthase(PTPS), sepiapterin reductase(SR)의 효소활성을 ammonium sulfate 단백질 농축액에서 분석한 결과 GTPCH와 PTPS의 활성은 팡이실에서 꼬리홀씨에 비해 약 2배 정도 높은 값을 보여주었다. 반면 SR의 활성은 오히려 꼬리홀씨에서 10배 정도 높은 것으로 분석되었다. 그리고 Northern blot 분석 결과 SR의 전사물도 꼬리홀씨에서 훨씬 많이 검출되었다. 이러한 결과들은 tetrahydrobiopterin이 Allomyces macrogynus의 팡이실 분화단계에 관여하고 있음을 추정케하는 한편 SR의 생리활성과 관련된 의문을 제기하고 있다.

• BMB Reports
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• 제43권9호
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• pp.584-592
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• 2010

Tetrahydrobiopterin (BH4) is a multifunctional cofactor of aromatic amino acid hydroxylases and nitric oxide synthase (NOS) as well as an intracellular antioxidant in animals. Through regulation of NOS activity BH4 plays a pivotal role not only in a variety of normal cellular functions but also in the pathogenesis of cardiovascular and neurodegenerative diseases, which develop under oxidative stress conditions. It appears that a balanced interplay between BH4 and NOS is crucial for cellular fate. If cellular BH4 homeostasis maintained by BH4 synthesis and regeneration fails to cope with increased oxidative stress, NOS is uncoupled to generate superoxide rather than NO and, in turn, exacerbates impaired BH4 homeostasis, thereby leading to cell death. The fundamental biochemical events involved in the BH4-NOS interplay are essentially the same, as revealed in mammalian endothelial, cardiac, and neuronal cells. This review summarizes information on the cellular BH4 homeostasis in mammals, focusing on its regulation under normal and oxidative stress conditions.

• BMB Reports
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• 제43권9호
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• pp.593-598
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• 2010

Tetrahydrobiopterin ($BH_4$) is a pivotal cofactor for enzymes responsible for the synthesis and release of monoamine neurotransmitters including dopamine and serotonin as well as the release of glutamate. Deficiencies in $BH_4$ levels and reduced activities of $BH_4$-associated enzymes have been recently reported in patients with schizophrenia. Accordingly, it is possible that abnormalities in the biochemical cascades regulated by $BH_4$ may alter DA, 5-HT and Glu neurotransmission, and consequently contribute to the pathophysiology of different neuropsychiatric diseases including schizophrenia. The development of a novel strain of mutant mice that is deficient in $BH_4$ by knocking out the expression of a functional sepiapterin reductase gene (spr -/-) has added new insights into the potential role of $BH_4$ in the pathophysiology and improved treatment of schizophrenia.

• Journal of Korean Neurosurgical Society
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• 제30권9호
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• pp.1059-1064
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• 2001

Objective : 6R-Tetrahydrobiopterin(BH4) is a cofactor for the aromatic amino acid hydroxylases which is essential for the biosynthesis of catecholamines and serotonin. It also acts as a cofactor for nitric oxide synthase, and stimulates the release of some neurotransmitters such as dopamine, serotonin, acetylcholine and glutamate. Recently, it has been reported that BH4 could induce cellular proliferation and enhance neuronal survival. This study was performed to investigate the antioxidative effect of BH4 on the various oxidative insults in mouse cerebral cortical cell cultures. Methods : Iron ion(FeCl2), zinc ion(ZnCl2), sodium nitroprusside(SNP) and buthionine sulfoximine(BSO, a glutathione depletor) were used as oxidants. Cell death was assessed by measurement of lactate dehydrogenase efflux to bathing media at the end of exposure. Result : All 4 oxidants induced neuronal cell death associated with cell body swelling, which was markedly inhibited by trolox($100{\mu}M$), a vitamin E analog. BH4($10-100{\mu}M$) markedly inhibited the neuronal cell death induced by all 4 oxidants($20{\mu}M\;Cu^{2+}$, $20{\mu}M\;Zn^{2+}$, $1{\mu}M$ SNP or 1mM BSO). However, BH4 failed to inhibit the neuronal cell death induced by 24hr exposure to $20{\mu}M$ NMDA. Conculsion : These results suggest that BH4 has antioxidative action independently of any actions of enzyme cofactor.

• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1709-1713
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• 2015

Sepiapterin is a precursor for the synthesis of tetrahydrobiopterin (BH4), which is a wellknown cofactor for aromatic amino acid hydroxylation and nitric oxide synthesis in higher mammals. In this study, a recombinant Escherichia coli BL21(DE3) strain harboring cyanobacterial guanosine 5’-triphosphate cyclohydrolase 1 (GCH1) and human 6-pyruvoyltetrahydropterin synthase (PTPS) genes was constructed to produce sepiapterin. The optimum conditions for T₇ promoter–driven expression of GCH1 and PTPS were 30℃ and 0.1 mM isopropyl-β-D-thioglucopyranoside (IPTG). The maximum sepiapterin concentration of 88.1 ± 2.4 mg/l was obtained in a batch cultivation of the recombinant E. coli, corresponding to an 18-fold increase in sepiapterin production compared with the control condition (37℃ and 1 mM IPTG).

• 대한유전성대사질환학회지
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• 제15권2호
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• pp.55-58
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• 2015

Tetrahydrobiopterin ($BH_4$) can normalize blood phenylalanine (Phe) levels in $BH_4$ deficiency, but typically not in phenylketonuria (PKU). In 1999, Kure et al. reported that some PKU patients showed decreased blood Phe levels after $BH_4$ loading, and thereafter, those PKU patients were identified by neonatal PKU screening. A natural cofactor for phenylalanine hydroxylase (PAH) is a 6R-isomer of $BH_4$, which is first synthesized in Japan as Sapropterin dihydrochloride (Biopten$^{(R)}$) in 1982. In Japan, Biopten$^{(R)}$ is first approved for the treatment of $BH_4$ deficiency in 1992, and then for $BH_4$-responsive PAH deficiency (BPKU) in 2008. The discovery of BPKU has vast clinical implications. After Biopten$^{(R)}$ (Kuvan$^{(R)}$) is available for the treatment of BPKU, the QOL of both patients and their families were improved very much, since the serum phenylalanine levels were controlled within 4 mg/dL by $BH_4$ mono-therapy with a normal diet or $BH_4$ combined use of mild phenylalanine-restricted diet. Biopten$^{(R)}$ therapy in patients with BPKU is highly efficacious (70%) at maintaining serum Phe levels within recommended control range and provides excellent safety at least average use period of 10 years (range, 1-17 years) with no unwarranted side effects in Japan. In addition it has been confirmed that sapropterin therapy initiated before 4 years of age was very effective to maintain plasma Phe levels within the favorable range and was safe in Japanese patients with BPKU.

• The Korean Journal of Physiology and Pharmacology
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• 제18권2호
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• pp.129-134
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• 2014

It has been suggested that transition metal ions such as iron can produce an oxidative injuries to nigrostriatal dopaminergic neurons, like Parkinson's disease (PD) and subsequent compensative increase of tetrahydrobiopterin ($BH_4$) during the disease progression induces the aggravation of dopaminergic neurodegeneration in striatum. It had been established that the direct administration of $BH_4$ into neuron would induce the neuronal toxicity in vitro. To elucidate a role of $BH_4$ in pathogenesis in the PD in vivo, we assessed the changes of dopamine (DA) and $BH_4$ at striatum in unilateral intranigral iron infused PD rat model. The ipsistriatal DA and $BH_4$ levels were significantly increased at 0.5 to 1 d and were continually depleting during 2 to 7 d after intranigral iron infusion. The turnover rate of $BH_4$ was higher than that of DA in early phase. However, the expression level of GTP-cyclohydrolase I mRNA in striatum was steadily increased after iron administration. These results suggest that the accumulation of intranigral iron leads to generation of oxidative stress which damage to dopaminergic neurons and causes increased release of $BH_4$ in the dopaminergic neuron. The degenerating dopaminergic neurons decrease the synthesis and release of both $BH_4$ and DA in vivo that are relevance to the progression of PD. Based on these data, we propose that the increase of $BH_4$ can deteriorate the disease progression in early phase of PD, and the inhibition of $BH_4$ increase could be a strategy for PD treatment.

• 대한화장품학회지
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• 제33권1호
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• pp.53-60
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• 2007

테린 계열의 화합물은 생체 내에 존재하여 여러 가지 효소들의 cofactor로써의 역할을 담당하며, 활성 산소에 대하여 제거 작용을 갖는 비단백질 화합물로서 널리 알려져 있다. 테린 계열의 화합물은 (6R)-5,6,7,8-tetrahydrobiopterin (이하 $6-BH_4$)인 완전히 환원된 형태로 활성을 가지며 공기에 노출되었을 경우 쉽게 산화 형태로 전환된다. $6-BH_4$의 결핍 증상으로서 정신 질환관련된 파킨슨 질환, 알츠하이머 질환, 우울증 등의 증상이 있으며, 피부 질환으로는 백반증이 있다. 최근에는 $6-BH_4$의 멜라닌합성 저해와 관련된 연구가 수행되어지고 있다. 본 연구에서는 $6-BH_4$와 유도체인 (6R)-5-methyl-5,6,7,8-tetrahydrobiopterin (이하 methyl-$BH_4$)의 항산화 효능과 미백 효능 및 자외선 손상 방어 효능에 관한 연구를 수행하였다. 테린 화합물의 DPPH 라디칼소거능 평가 결과 항산화 표준 물질인 quercetin과 유사한 효능을 갖는 항산화 물질임을 확인하였으며, 피부 세포주에서의 세포독성이 없는 안전한 물질임을 확인하였다. 또한 미백 효능을 평가하기 위하여 효소 수준에서의 tyrosinase 활성 저해능과 세포수준에서의 tyrosinase, TRP-1단백질의 발현 저해 효능을 확인하였다. in vivo에서의 미백 효능 평가 결과 역시 증류수 처리군과 비교시 테린 화합물 처리군에서 멜라닌 수치가 감소하는 것을 확인할 수 있었다. 테린 화합물의 또 다른 효능으로서 항산화효능을 기반으로 하는 자외선 손상 방어 효능을 평가한 결과, 자외선에 의해 유도되는 cytokines의 발현양을 감소시켰으며, 멜라닌의 합성을 저해하는 것을 확인할 수 있었다. 이러한 결과들로부터 테린 화합물의 화장료적 특성을 확인할 수 있었다.

• BMB Reports
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• 제46권1호
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• pp.37-40
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• 2013

CY-007 and CY-049 pteridine glycosyltransferases (PGTs) that differ in sugar donor specificity to catalyze either glucose or xylose transfer to tetrahydrobiopterin were studied here to uncover the structural determinants necessary for the specificity. The importance of the C-terminal domain and its residues 218 and 258 that are different between the two PGTs was assessed via structure-guided domain swapping or single and dual amino acid substitutions. Catalytic activity and selectivity were altered in all the mutants (2 chimeric and 6 substitution) to accept both UDP-glucose and UDP-xylose. In addition, the wild type activities were improved 1.6-4.2 fold in 4 substitution mutants and activity was observed towards another substrate UDP-N-acetylglucosamine in all the substitution mutants from CY-007 PGT. The results strongly support essential role of the C-terminal domain and the two residues for catalysis as well as sugar donor specificity, bringing insight into the structural features of the PGTs.

• Journal of Microbiology
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• 제43권2호
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• pp.191-195
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• 2005

In this study, we attempted to characterize the Synechococcus sp. pee 7942 mutant resultant from a disruption in the gene encoding UDP-glucose: tetrahydrobiopterin a-glucosyltransferase (BGluT). 2D­PAGE followed by MALDI-TOF mass spectrometry revealed that phycocyanin rod linker protein 33K was one of the proteins expressed at lower level in the BGluT mutant. BGluT mutant cells were also determined to be more sensitive to high light stress. This is because photosynthetic O$_2$ exchange rates were significantly decreased, due to the reduced number of functional PSIs relative to the wild type cells. These results suggested that, in Synechococcus sp. pee 7942, BH4-glucoside might be involved in photosynthetic photoprotection.