• 한국식품영양과학회지
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• 제24권3호
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• pp.409-414
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• 1995

모델시스템에서 얻어진 tyrosinase의 효소적 산화반응생성물 (enzymatic oxidation products of tyrosine ; EOPTs) 그리고 동 반응의 중간 또는 최종 물질로 알려진 두가지의 표준 물질 즉, dihydroxyphenylalanine (DOPA)과 melanin에 대한 일련의 항산화 특성을 살펴보았다. Tyrosine-tyrosinase 반응시스템(pH 6.5, 온도 $25^{\circ}C$, 시간 0~120분)에서 얻어진 EOPTs는 전반적으로 200~210, 280, 310~320 그리고 450~490mm에서 정점을 갖는 광학적 흡수특성을 보였으며 15분 후에는 450~520nm에서 강한 흡수특성을 나타냈다. EOPTs의 리놀레산에 대한 산화반응 억제 효과는 다 같이 최초 반응 물질인 tyrosine 보다는 현저히 높고 반응초기(1~3분)의 것이 후기의 것들 보다 높았다. 또한 tyrosine, DOPA 및 melanin 등의 표준물질에 있어서는 tyrosine 보다는 다른 두 물질에서 항상화 효과가 더 높았고 그 중 DOPA의 항산화력이 가장 높게 나타났다. 한편 이들의 유리기 소거능은 tyrosine 보다는 다른 두 표준물질에서 높았으며 이러한 산화반응 물질들은 다양한 항산화 특성을 나타내고 있으며 특히 최종 갈변생성물 보다는 중간물질에서 더 높은 효과를 보이고 있다. 그러나 아직은 그 작용 메카니즘이 분명치 않으며 앞으로 더 규명되어야 할 것으로 생각된다.

• Archives of Pharmacal Research
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• 제21권6호
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• pp.782-784
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• 1998

Ginseng total saponin (GTS) can modulate dopaminergic activity at both presynaptic and postsynaptic dopamine receptors (Kim et al, 1998). The present study investigated t he effect of GTS on the bovine adrenal tyrosine hydroxylase (TH), which catalyze L/tyrosine to DOP. GTS inhibited the bovine adrenal TH by 42.4, 51.5 and 55.3% at concentrations of 40, 80 and 100${\mu}g$/ml, respectively. The IC50 value of GTS was 77.5${\mu}g$/ml. GTS exhibited noncompetitive inhibition with a substrate L-tyrosine. The Ki value was 155${\mu}g$/ml.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.209-209
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• 1996

Muscarinic acetylcholine receptors contain two highly conserved tyrosine residues which are located within or at the extracellular border of the second transmembrane domain. These tyrosine residues are located at positions 82 and 85 of the sequence of the ml subtype of muscarinic receptors. In this wok, we studied the involvement of these two residues in ligand binding to and agonist-induced activation this receptor subtype. our data suggest an important role for these two tyrosines in these processes, with a more prominent role for the tyrosine residue located at position 82 than that located at position 85. Evidence is also provided that while the aromatic moiety of these tyrosine residues is important for antagonist binding, both this moiety and the tyrosine phenolic hydroxyl group are involved in agonist binding and receptor activation.

• Journal of Nutrition and Health
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• 제26권7호
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• pp.858-866
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• 1993

S.D.rats were fed with 3.4% tyrosine supplemented diet for 5 days. Tyrosine diet had no effects on brain NE and MHPG-SO4 levels in non-stressed rats. When these animals were given 3 hr-immobilization stress, they responded in a manner that coped better to the stress. This was measured by the increase in brain MHPG-SO4 indicating the increase in norepinephrine turnover by the stressed animals. When rats were stressed, fed basal or high-tyrosine diet, brain tyrosine concentration dropped more than 26% over the non-stress control animals. 3-hr immobilization stress also decreased brain NE levels. However, while the stress resulted in a significant decrease(p<0.05) of brain NE in basal diet, the decrease was not significant in high-TYR diet group. And as the stress index, serum corticosterone, glucose, and free fatty acid concentratons also were assayed. In this study, it was found that high-TYR diet prevented the stress-induced depletion of brain NE and suppressed the rise in serum corticosterone, glucose, and free fatty acid. These results suggest that high-TYR diet increases the coping ability of body to stress.

• Archives of Pharmacal Research
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• 제18권6호
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• pp.371-375
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• 1995

Erythropoietin (EPO), a glycoprotein hormone, regulates the proliferation and differentiation of ereythroid progenitor cells. Many attempts have been made to identify the functionally important amino acids of the hormone. One of those early studies has found that heavy redioiodination of EPO caused the loss of its biological activity, suggesting some important role of one of the four tyrosine residues (Goldwasser, 1981). Thus, in this study, we have generated and tested four $Tyr{\dashrightarrow}Phe$ substitution mutants to clarify the possible role of the tyrosine residue(s) in the hormone's Tyrosine residue(s) in the hormone's biological activity. When the mutant and wild type EPO cDBAs were transfected into COS-7 cells and the biological activities of the muteins were assayed using the primary murine erythroid spleen cells, no mutation tested was found to affect the biological activity of the hormone. Thus we conclude that, contrary to the previous observation, none of the four tyrosine in eryghropoietin is critically involved in the binding of the hormone to its receptor.

• International journal of thyroidology
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• 제11권2호
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• pp.75-77
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• 2018

Tyrosine kinase inhibitor is known to prolong progression free survival in radioiodine refractory thyroid cancer patients. Fatigue/asthenia/malaise is one of most common adverse events by the tyrosine kinase inhibitor treatment, and management of the adverse event is important to keep the drug medication longer which is essential for the survival benefit. In the case report, a radioiodine refractory thyroid cancer patient receiving tyrosine kinase inhibitor experienced severe fatigue, and a pathologic fracture of right humerus occurred by slipping down which was tightly linked with the adverse event of the drug. The pathologic fracture was surgically well managed and the adverse event was well controlled by supportive managements combined with dose reduction of the tyrosine kinase inhibitor. The drug administration to the patient was kept more than 1 year without progression of the disease.

• Applied Biological Chemistry
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• 제38권1호
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• pp.13-19
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• 1995

Phenylalanine 생산시 tyrosine이 부생되지 않도록 tyrA유전자 발현이 낮은 여러 가지 온도조절형 plasmid를 제작하였으며, phenylalanine 생산균주인 대장균 AT2471$[tyrA^-,\;thi^-]$은 tyrosine 영양요구 변이균주이므로 생산배지에 tyro-sine 첨가없이 phenylalanine을 생산할 수 있도록 하기 위하여 tyrosine 복귀변이균주를 분리하여 phenylalanine 생산을 검토하였다. 2.5 l jar fermenter를 사용하여 tyrosine 첨가없이 phenylalanine 생산을 검토하여 대장균 AT2471/pSY146A, 대장균 AT2471 tyrosine 복귀변이균주 5/pSY111-14를 $39^{\circ}C$에서 55시간 배양한 결과 각각 12 g/l, 15 g/l를 생산하였다.

• 생명과학회지
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• 제7권3호
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• pp.198-204
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• 1997

tyrosine 인산화효소계를 통한 신호전달은 신경의 발생과 연접환성조절에 중요한 역할을 한다. 흰쥐 소뇌의 연접후치밀질에 존재하는 tyrosine 함유 당백질들을 조사하기 위하여 immunoblot 분석을 한 결과, 소뇌 연접후치밀질의 전반적인 단백질조성은 전뇌와 비슷하였다. phosphotyrosine 특이성 항체로, immunobolot 한 결과 소뇌의 주된 tyrosine 인산화 단백질은 50 kD 크기의 새로운 단백질이었다. PSD-50로 명명한 이 단백질은 SDS-PAGE에서 $\alpha$CaMKII와 같은 위치에 이동하였다. 그러나 소뇌에는 전뇌에 비하여 적은량의 $\alpha$CaMKII가 존재함에도 불구하고 전뇌보다 더 강한 phosphotyrosine immunoblot signal을 보이는 것으로 보아 PSD-50는 아마도 $\alpha$CaMKII와는 다른 단백질로 추정된다.

• BMB Reports
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• 제34권1호
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• pp.33-38
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• 2001

The human PTK6 (also known as Brk) polypeptide, which is deduced from its full-length cDNA, represents a non-receptor protein tyrosine kinase (PTK). It contains SH3, SH2, and tyrosine kinase catalytic domains that are closely related to Src family members. We generated an antihuman PTK6 antibody by immunizing rabbits with a PTK6-specific oligopeptide conjugated to BSA, which corresponds to 11 amino acid residues near the C-terminus. An immunoblot analysis with the antibody detected an expected 52-kDa band in various mammalian transformed cell lines. Immunoprecipitation and immunoblot analyses demonstrated that PTK6 is phosphorylated on the tyrosine residues) and interacts with approximately a 23-kDa tyrosine-phosphorylated polypeptide (most likely a substrate of PTK6) in breast carcinoma T-47D cells. An immunofluorescence analysis demonstrated that PTK6 is localized throughout the cytoplasm of T-47D cells. These results support a possible role for PTK6 in the intracellular signal transduction through tyrosine phosphorylation.

• The Korean Journal of Physiology and Pharmacology
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• 제4권3호
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• pp.211-217
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• 2000

Paxillin is a regulatory component of the complex of cytoskeletal proteins that link the actin cytoskeleton to the plasma membrane. However, the role of paxillin during smooth muscle contraction is unclear. We investigated a possible role for the membrane-associated dense plaque protein paxillin in the regulation of contraction in rat aortic vascular smooth muscle. The tyrosine phosphorylation of paxillin, which was increased by norepinephrine, reached a peak level after 1 min stimulation and then decreased with time. However, norepinephrine induced a sustained contraction that reached a steady state 30 min after application. Pretreatment with tyrphostin, an inhibitor of tyrosine kinase, inhibited the tyrosine phosphorylation of paxillin and also the contraction stimulated by norepinephrine. Both inhibitions were concentration-dependent, and the degree of correlation between them was high. These results show that, in rat aortic smooth muscle, tyrosine kinase(s) activated by norepinephrine may phosphorylate the tyrosine residues of paxillin, thereby providing a source of regulation during vascular smooth muscle contraction.