• Journal of Microbiology
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• v.42 no.1
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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.

• Journal of Life Science
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• v.13 no.4
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• pp.383-389
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• 2003

A cDNA (SeMIPS) encoding myo-inositol 1-phosphate synthase has been isolated from developing sesame (Sesamum indicum L. cv. Dan-Baek) seeds and its structure and function analyzed. The SeMIPS protein was highly homologous with those from plant species (88-94%), while a much lower degree of sequence homology (60%) was found with that of human. The functional domains commonly found in MIPS protein were identified and their amino acid residues were compared with each other. Northern blot indicated that the expression of the SeMIPS gene might be organ-specifically regulated. A complementation assay based on a yeast mutant system confirmed that the SeMIPS gene encodes a myo-inositol 1-phosphate synthase (MIPS) of sesame by showing functional expression of the SeMIPS cDNA in the yeast mutants containing the disrupted INO1 gene.

• Proceedings of the KSCN Conference
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• 1998.05a
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• pp.81-81
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• 1998

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.95-95
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• 2003

Inositol은 세포의증식 및 정보전달과정에 관여하는 phosphatidylinositol (PI)의 구성성분으로서 중요한 세포내 기능을 수행한다. P1는 세포내에서 특이적 인산화효소에 의하여 Pl4-phosphate(PIP), Pl4,5-phosphate($PIP_2$)로 변환되며 PIP$_2$는 phospholipase C(PLC)에 의하여 세포내 second messengers인 1,2-diacylglycerol (DAG)와 inositol 1,4,5-triphosphate ($IP_3$)로 변환된다. 이렇게 생산된 DAG와 IP3는 각각 protein kinase C의 활성과 $Ca^{2++}$의 동원에 관여하여 다양한 세포내 신호전달에 관여하는 것으로 보고되고 있다. 또한 mouse에서 $IP_3$의 작용에 의한 $Ca^{2++}$의 상승은 난모세포의 성숙분열이 촉진되고 돼지 난포세포에 있어서도 PI대사가 일어나고 있는 것으로 보고되고 있다. 본 연구에서는 돼지 미성숙 난모세포의 성숙과 단위발생에 미치는 inositol의 영향을 확인하기 위하여 실시하였다. inositol의 농도가 난포란의 성숙에 미치는 영향을 검토하기 위하여 난포란을 각각 $150 \mu mole$, $250 \mu mole$, $350 \mu mole$, inositol을 포함하는 Whitten's 배양액에서 44시간 성숙시킨 결과 $93.57 \pm 4.21, 93.91 \pm 2.71, 92.96 \pm 3.58%$가 성숙되어 대조구의 $87.10 \pm 4.21$보다 유의적(P<0.05)으로 차이를 나타내었다. 난포란의 등급에 따른 inositol의 영향을 확인하기 위하여 형태적으로 난구세포가 치밀한 난포란과 난구세포가 치밀하지 않은 난포란을 $250 \mu mole$ inositol을 포함하는 Whitten's 배양액에서 성숙을 유도한 결과 난구세포가 치밀한 난포란과 난구세포가 치밀하지 않은 난포란에서 inositol을 첨가하였을 때 성숙율은 각각 $95.35 \pm 2.22와 63.55 \pm 8.12$로 inositol을 첨가하지 않은 대조구보다($89.21 \pm 3.69와 48.56 \pm 8.99$) 유의적인 차이를 보였다. 난구세포가 inositol에 의한 성숙에 미치는 영향을 확인하기 위하여 난구세포를 제거한 난포란을 inositol을 포함하는 배지에서 성숙을 유도한 결과 inositol을 첨가하지 않은 처리구보다 양호한 성숙율을 보였다.

• Journal of environmental and Sanitary engineering
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• v.16 no.4
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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.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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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)

• Applied Biological Chemistry
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• v.19 no.3
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• pp.121-129
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• 1976

A high concentration of myo-Inositol in rat's milk was observed (61-91mg. of myo-Inositol per 100g of milk) by gas-liquid chromatographic method, using a 3% SE-52 column. Feeding experiments showed that approximately 85% of myo-Inositol in milk was from dietary origin: the rest was considered to be synthesized by 1L-myo-Inositol-1-phosphate lyase. Results suggested that the biosynthesis was not sufficiently high to permit the maintenance of its myo-Inositol level in milk. However, study $using(^{14}C)-glucose$ injection into lactating female rats confirmed biosynthesis of myo-Inositol from glucose in mammary gland. This biosynthesis reached a maximum within an hour after $(^{14}C)-glucose$ injection intraperitoneally as lactose biosynthesis did. Study using $(^3H)-myo-Inositol$ confirmed that most of the myo-Inositol in milk was transported from blood plasma myo-Inositol against a concentration gradient. About four hours after the beginning of the injection of $(^{14}C)-glucose$, the specific radioactivity of myo-Inositol in milk was 8% of that of glucose in the blood. When $(^3H)-myo-Inositol$ was injected, the specific radioactivity of myo-Inositol in milk was about 26% of that of blood six hours after injection.

• KSBB Journal
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• v.26 no.4
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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.

• BMB Reports
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• v.38 no.3
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• pp.360-365
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• 2005

Membrane inositol glycerophospholipid (IGP) is metabolized to phosphatidylinositol-4-phosphate (PIP), phosphatidylinositol-4, 5-bisphosphate ($PIP_2$), and inositol triphosphate ($IP_3$) in signaling transduction. This study was carried out to determine the subclasses of IGP involved in signaling pathway. The acyl chain moieties of the phospholipids are easily modulated by dietary fatty acids. We analyzed acyl chain composition of IGP 3-subclasses, PIP and $PIP_2$ from rat brain after feeding sunflower seed oil enriched with linoleic acid or fish oil high in eicosapentaenoic acid and docosahexaenoic acid. Long chain polyunsaturated fatty acids (LCPUFA) as eicosapentaenoic acid and docosahexaenoic acid were not incorporated into ether-linked IGP (alkenylacylglycerophosphoinositol and alkylacyl-glycerophosphoinositol), PIP and $PIP_2$, while diacyl-glycerophosphoinositol (GPI) contained high LCPUFA. These results suggest that PIP might be phosphorylated from only the ether-linked IGP (alkenylacyl- and alkylacyl species) but not from diacyl subclass for signals to intracellular responses in the plasma membrane of rat brain.

• Journal of environmental and Sanitary engineering
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• v.14 no.1
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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.