• Journal of Microbiology
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• 제42권1호
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• pp.20-24
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• 2004

Cloned myo-inositol-1-phosphate synthase (INOS) of Drosophila melanogaster was expressed in Escherichia coli, and purified using a His-affinity column. The purified INOS required NAD$\^$+/ for the conversion of glucose-6-phosphate to inositol-1-phosphate. The optimum pH for myo-inositol-1-phosphate synthase is 7.5, and the maximum activity was measured at 40$^{\circ}C$. The molecular weight of the native enzyme, as determined by gel filtration, was approximately M$\_$r/ 271,000${\pm}$15,000. A single subunit of approximately M$\_$r/ 62,000${\pm}$5,000 was detected upon SDS-polyacrylamide gel electrophoresis. The Michaelis ($K_{m}$) and dissociation constants for glucose-6-phosphate were 3.5 and 3.7 mM, whereas for the cofactor NAD$\^$+/ these were 0.42 and 0.4 mM, respectively.

• Applied Biological Chemistry
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• 제19권3호
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• pp.121-129
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• 1976

우유중에 상당량 존재하는 myo-Inositol의 생성을 알아보기 위하여 3% SE-52를 충진시킨 gas-liquid chromatography에 의해 myo-Inositol의 정량을 행하고 이 myo-Inositol의 유래를 feeding 실험과 $(^{14}C)-glucose$와 (3H)-myo-Inositol을 쥐에 주사한 실험으로 알아 븐 결과 다음과 같은 결과를 얻었다. 1. 쥐우유를 G.L.C. 방법으로 분석하여 우유 100gm.당 61-91mg.의 myo-Inositol (free)을 얻었다. 2. Feeding 실험 결과 우유 myo-Inositol의 85%는 diet에서 흡수되었고 나머지는 mammary gland에서 합성된 것으로 나타났다. 3. $(^{14}C)-glucose$에서 $(^{14}C)-myo-Inositol$ 생성은 lactose의 생성과 비슷하게 한시간이내에 최고에 달하였다. 4. $(^3H)-myo-Inositol$을 lactating rat에 주사하여 실험한 결과 우유 myo-Inositol의 대부분은 혈액 myo-Inositol에서 유래되었다. $(^{14}C)-glucose$를 주사한 후 우유중에 나타난 myo-Inositol의 비방사능(比放射能)은 4시간 후에 혈액 glucose의 8%였다.

• 생명과학회지
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• 제13권4호
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• pp.383-389
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• 2003

1845 bp의 SeMIPS cDNA를 발육종자에서 분리하고 이 cDNA의 구조와 특성을 분석하였다. 이 cDNA는 엽록체로 향하는 신호펩타이드의 아미노산 서열이 존재하지 않아서 세포질형 MIPS로 예상되었다. 또한 이 cDNA의 아미노산 서열의 유사성은 다른 MIPS와 비교한 결과 60-94%의 높은 아미노산 서열 유사성을 보여주었으며, 특히 식물끼리의 유사성이 훨씬 높았다. Northern blot분석에서 볼 때 참깨의 조직별 SeMIPS mRNA는 완숙종자, 줄기, 뿌리에서는 약하게 발현되었고, 잎에서는 비교적 강하게 발현되는 현상을 보여주었다. Yeast 돌연변이체를 통한 활성 시험에서는 SeMIPS가 myo-inositol 1-phosphate synthase의 효소활성을 가지고 있다는 실험적 증거를 얻었으며, C-말단 아미노산 20개가 효소활성에 필수적이라는 사실이 본 실험에서 검증되었다.

• 대한지역사회영양학회:학술대회논문집
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• 대한지역사회영양학회 1998년도 춘계학술대회:경제위기시대의 합리적인 식생활
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• pp.81-81
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• 1998

• BMB Reports
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• 제32권3호
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• pp.294-298
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• 1999

Myo-inositol monophosphate phosphatase is a key enzyme in the phosphoinositide cell-signaling system. Incubation of myo-inositol monophosphate phosphatase from porcine brain with N-bromosuccinimide (NBS) resulted in a time-dependent loss of enzyme activity. The inactivation followed pseudo-first-order kinetics with the second-order rate constant of $3.8{\times}10^3\;M^{-1}min^{-1}$. The time course of the reaction was significantly affected by the substrate myo-inositol-1-phosphate, which afforded complete protection against the loss of catalytic activity. Spectrophotometric studies indicated that about one oxindole group per molecule of enzyme was formed following complete loss of enzymatic activity. It is suggested that the catalytic function of myo-inositol monophosphate phosphatase is modulated by the binding of NBS to a specific tryptophan residue at or near the substrate binding site of the enzyme.

• 환경위생공학
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• 제16권4호
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• pp.1-8
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• 2001

We have previously demonstrated that sodium molybdate(Mo) improved lead-intoxicated status by enhancing the metabolism of mao-inositol-related phospholipids in sciatic nerves isolated from rats. In this study, in order to address the reduction mechanism of Mo for lead toxicity, effects of Mo on cystidine-diglyceride transferase, phosphatidylinositol kinase, and phosphatidyl inositol-4-phosphate kinase, involved in mao-inositol metabolism of nerve, were investigated in vivo and in vitro. Mo significantly increased the activities of cystidine- diglyceride transferase and phosphatidylinositol kinase in lead-intoxicated rat, and the pattern of increase was dose-dependent manner. However, Mo did not affect the activity of phosp- hatidylinositiol-4-phosphate kinase in normal and lead-intoxicated rats. We also found that Mo affected the activities of phopholipid metabolism-related enzymes not by the indirect manner such as activation of another metabolic pathway but by the direct manner. These results suggest that the improvement mechanism of Mo for lead-intoxicated status might be a normalization of the activities of phospholipid metabolism-related enzymes in sciatic nerve.

• 환경위생공학
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• 제14권1호
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• pp.88-96
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• 1999

The effect of acute cadmium-neuropathy on phospholipid metabolism in rat sciatic nerve was investigated. An animal model of cadmium neuropathy was induced by feeding diet containing cadmium to Sprague-Dawley rat for two weeks. Four weeks aged Sprague-Dawley rats were divided into four groups : normal control group, 10ppm-cadmium treated group, 100ppm-cadmium treated group, 1000ppm-cadmium treated group, reference drug, myo-inositol-treated group. All rats were sacrificed at the end of two weeks. The rate of incorporation of 2-[3H]myo-inositol into polyphosphinositide was significantly decreased while the rates of incorporation into phospholipid of titratedserine, ethanolamine and choline were unchanged in sciatic nerve obtained from cadmium-treated rat. Continuously the activities of three enzymes concerned with inositol phospholiped metabolism were measured in homogenates of rat sciatic nerves. Cystidine diglyceride transferase and phophatidylinositol kinase showed significantly decreased activities while phosphatidylinositol-4-phosphate kinase did not show any significant change in activity by cadmium treatment. However these deficits of inositol phospholipid metabolism were ameliorated by myo-inositol administration and these effectiveness were more potent in lower dose cadmiumtreated rats than higher dose cadmium-treated rats. These results suggest that cadmium intoxicated peripheral nerve with perturbation of the ployphosphoinositide metabolism and alteration of the enzyme activity which concerned with myo-inositol metabolism.

• KSBB Journal
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• 제26권4호
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• pp.300-304
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• 2011

Phytases are hydrolytic enzymes that catalyze the sequential hydrolysis of phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate) to myo-inositols with lower numbers of phosphate groups. Two types of phytases have been identified which initiate hydrolysis of the phytic acid at either the 3- or 6- position of the inositol ring. In the present investigation, a mathematical model was proposed and computed to estimate maximum enzyme reaction rate constants which fit the experimental data obtained by other authors. Although the data points were scattered to some extent, good agreement was found between the model and the experiment data. It appears that the maximum rate constants of removal of the first, second, and third phosphate groups were not equal. Also there was neither a steady trend upward or downward in the rate constants with the stepwise hydrolysis reactions.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2002년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.179-180
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• 2002

Phytase는 phytic acid (myo-inositol 1,2,3,4,5,6 hexakis dihydrogen phosphate)를 분해하여 phosphate와 phosphate inositol를 만드는 효소이다. Phytic acid는 가축의 사료로 사용하고 있는 곡물의 경우 인함량의 50∼70％를 차지하지만, 물고기, 닭, 돼지와 같은 단위동물은 생체 내에 phytic acid를 분해하는 phytase가 존재하지 않기 때문에 식물성 인의 이용률이 극히 낮아서 성장에 필요한 인을 무기물 형태로 외부에서 따로 충분히 공급해줘야만 한다. (중략)

• 한국균학회지
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• 제27권4호통권91호
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• pp.299-303
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• 1999

Aspergillus ficuum이 발효조의 배양액에서 phytase를 가장 많이 분비 생산하는 시간은 5일째였다. 이 phytase를 ultrafiltration, cation exchange column, 그리고 anion exchange column으로 최종 정제하여 SDS-PAGE로 분석하여 본 결과 단일 band로 약90,000의 분자량을 가진 것으로 나타났다. 정제된 phytase를 사용하여 phytase에 대한 항체를 생산하였고 titer는 1/25,000로 결정하였다.