대장균 Strain B 와 B / r 에 있어서 Acyl Phosphatidyl Glycerol 의 생합성 기작에 관한 연구

조기승,홍승덕,장정순,이강석 ( Key Seung Cho,Seung Duk Hong,Chung Soon Chang,Kang Suk Lee ) 생화학분자생물학회 1975 BMB Reports Vol.8 No.1

The present study has shown that phosphatidyl glycerol was converted to 3-sn-phosphatidyl-1`-(3`-acyl)-sn-glycerol(acyl phosphatidyl glycerol) by cell free extracts of Escherichia coli B and B/r. In this process, phosphatidyl glycerol was esterified directly rather than degraded to simpler compounds which are subsequently incorporated into acyl phosphatidyl glycerol. The enzyme, $quot;acyl phosphatidyl glycerol synthetase$quot;, which catalyzes the conversion of phosphatidyl glycerol to acyl phosphatidyl glycerol was found to reside solely in the praticulate fraction of E. coli homogenates. Two separate reactions were identified where one molecule of acyl phosphatidyl glycerol was synthesized from two molecules of phosphatidyl glycerol, in which phosphatidyl glycerol acted both as an acyl acceptor and a donor. In the other reaction, phosphatidyl ethanolamine appears to act as an acyl donor to synthesize acyl phosphatidyl glycerol. The formation of acyl phosphatidyl glycerol has an optimum pH value at pH 7.0 and calcium concentration of 6.0 mM. These results show a new pathway for the turnover of phosphatidyl glycerol in Escherichia coli.

The Mechanism of Acyl Phosphatidyl Glycerol Biosynthesis in Escherichia coli B and B/r

조기승,홍승덕,장정순,이강석,Cho, Key-Seung,Hong, Seung-Duk,Chang, Chung-Soon,Lee, Kang-Suk 생화학분자생물학회 1975 한국생화학회지 Vol.8 No.1

본 연구는 대장균 strain B와 B/r(Escherichia coli Band B/r)의 세포막 분획에의 해서 phosphatidyl glycerol이 3-sn-phosphatidyl-1'-(3'-acyl(-sn-glycerol(acyl phosphatidyl glycerol 로 전환되는 기작을 밝혔다. 이 과정에서 phosphatidyl glycerol은 더 간단한 화합물로 분해된 후 acyl phosphatidyl glycerol로 합성되는 것이 아니라 직접 acyl group이 옮겨져서 ester 결합을 하는 것으로 생각된다. Phosphatidyl glycerol이 acyl phosphatidyl glycerol로 전환되는 반응을 촉매하는 효소인 acyl phosphatidyl glycerol synthetase는 E. coli homogenate의 세포막 분획에 존재하는 것으로 밝혀졌다. Phosphatidyl glycerol이 acyl phosphatidyl glycerol로 전환됨에 있어서 두 개의 다른 반응 기작을 밝혔다. 두 분자의 phosphatidyl glycerol이 한 분자의 acyl phosphatidyl glycerol 을 합성하는 즉 phosphatidyl glycerol이 acyl group의 공여체와 수용체로 각각 작용하는 반응과 다른 반응은 phosphatidyl glycer이 이 수용체로 phosphatidyl ethanolamine이 acyl group 공여체로 작용하는 기작이다. Acyl phosphatidyl glycerol 생합성에 있어서 최적 pH 는 7.0이며 최적 calcium ion 농도는 6.0mM 이었다. 이 실험 결과는 대장균의 phosphatidyl glycerol의 새로운 대사과정을 밝혔다. The present study has shown that phosphatidyl glycerol was converted to 3-sn-phosphatidyl-1'-(3'-acyl)-sn-glycerol (acyl phosphatidyl glycerol) by cell free extracts of Escherichia coli Band B/r. In this process, phosphatidyl glycerol was esterified directly rather than degraded to simpler compounds which are subsequently incorporated into acyl phosphatidyl glycerol. The enzyme, "acyl phosphatidyl glycerol synthetase", which catalyzes the conversion of phosphatidyl glycerol to acyl phosphatidyl glycerol was found to reside solely in the praticulate fraction of E. coli homogenates. Two separate reactions were identified where one molecule of acyl phosphatidyl glycerol was synthesized from two molecules of phosphatidyl glycerol, in which phosphatidyl glycerol acted both as an acyl acceptor and a donor. In the other reaction, phosphatidyl ethanolamine appears to act as an acyl donor to synthesize acyl phosphatidyl glycerol. The formation of acyl phosphatidyl glycerol has an optimum pH value at pH 7.0 and calcium concentration of 6.0 mM. These results show a new pathway for the turnover of phosphatidyl glycerol in Escherichia coli.

적혈구 막에 관한 연구(I) Palmitoyl Carnitine에 의한 소 적혈구 막의 용해

이강순,장정순,조기승,이강석,Rhee, Kang-Soon,Chang, Chung-Soon,Cho, Key-Seung,Lee, Kang-Suk 생화학분자생물학회 1975 한국생화학회지 Vol.8 No.1

소의 적혈구막을 palmitoyl carnitine으로 처리하였을 때 단백질, 인지질 및 cholesterol이 동시에 완전히 용해되었고 palmitoyl carnitine에의 한 지질의 유리 및 micelle의 형성이 없는 것으로 보아 적혈구막은 lipoprotein 형태로 용해됨을 알았다. 소 적혈구막의 용해는 palmitoyl carnitine이 막의 lipoprotein과의 친수성 결합과 소수성 결합을 하므로써 용해되며 용해도는 소수성 결합 정도에의 존한다고 본다. Palmitoyl carnitine에의 한 혈구막 용해에 있어서 ATPase($Na^+$, $K^+$ dependent)와 glucose-6-phosphatase의 활성도는 저해 받지 않았으며 오히려 palmitoyl carnitine의 농도에 따라 각각 28-43%, 56-110%가 증가하였다. 용해된 막단백질에 있어 pH에 따른 용해도의 상태는 pH 5.0에서 92%의 단백질이 침전되었다. 용해된 막단백질을 Tris-glycine buffer, pH 8.3로 polyacrylamide gel electrophoresis를 행하였을 때 분자량이 450,000-70,000인 8개의 band로 분리되었다. The mechanism of solubilization of the ox-erythrocyte membrane was investigated with palmitoyl carnitine. When the membrane was treated with palmitoyl carnitine, the membrane protein, phospholipids and cholesterol were completely solubilized. It was confirmed that lipids were not liberated from membrane lipoprotein and not form micelles with palmitoyl carnitine. As a consequence, membrane was solubilized as a form of lipoprotein. In the present study, the results indicated that the erythrocyte membrane was solubilized by involvement of ionic and hydrophobic interaction of membrane lipoprotein with palmitoyl carnitine. The solubility of erythrocyte membrane depended upon the degree of the hydrophobic binding with palmitoyl carnitine. In the complete solubilized membrane, the activities of ATPase($Na^+$, $K^+$-dependent) and glucose-6-phosphatase were not affected or rather slightly increased of 28% and 56% as compared with intact membrane, respectively. The effect of pH on solubilized membrane protein showed that 92% of protein was precipitated at pH 5.0. In polyacrylamide gel electrophoresis with Tris-glycine buffer, pH 8.3, solubilized membrane protein was separated into 8 bands with molecular weight ranged from 450, 000 to 70, 000.

생쥐뇌 세포질 분획의 Acid 및 Alkaline Phosphatase의 특성 비교 연구

강창균,이영식,조기승,Kang, Chang-Gyun,Lee, Young-Seek,Cho, Key-Seung 생화학분자생물학회 1990 한국생화학회지 Vol.23 No.3

Acid and alkaline phosphatases from mouse brain cytosol fraction were separated and partially purified with 91 and 15 folds, respectively, by DEAE-cellulose column chromatography and Sephadex G-150 gel chromatography. Acid phosphatase (ACPase, EC 3.1.3.2) showed substrate specificity only to p-nitrophenylphosphate among the several substrates tried, such as, adenosine-3'-monophosphate (3'-AMP), adenosine-5'-monophosphate (5'-AMP), adenosine-5'-triphosphate (5'-ATP), glucose-6-phosphate (G-6-P), inositol-1'-monophosphate (IP), inositol-1,4,5-triphosphate $(IP_3)$ and p-nitrophenylphosphate (PNPP). On the other hand, alkaline phosphatase (ALPase, EC 3.1.3.1) showed to active to PNPP and IP substrates among them. ACPase and ALPase showed the maximum enzyme activities at pH 5.2 with 50 mM acetate buffer and at pH 7.8 with 50 mM Hepes buffer in the presence of $Mg^{2+}$, respectively. In the effect of $Na^+$ and $K^+$ on both ACPase and ALPase, these ions had no effect at all on ACPase, but 50 mM $Na^+$ and 100 mM $K^+$ showed maximum activation on ALPase by 3.4 times. Divalent cations, $Ca^{2+}$ and $Mg^{2+}$ showed no effect at all on ACPase, but 0.2 mM $Mg^{2+}$ stimulated ALPase significantly about 5 times. On the other hand, $Ca^{2+}$ represented competitive inhibition to $Mg^{2+}$ effect on ALPase. Ouabain had no effect at all, but L-phenylalanine showed a minor stimulation on ALPase. 생쥐 뇌 세포질 분획을 DEAE-Cellulose Chromatography와 Sephadex G-150 gel Chromatography 등에 의해 acid 및 alkaline phosphatase로 분리, 부분정제하였을 때 각각 91배와 15배의 정제율을 나타내는 분획을 얻었다. 이들의 기질특이성을 보았을 때, 사용한 여러 기질 중에서 acid phosphatase(ACPase)는 p-nitrophenylphosphate에만 작용하였으며, alkaline phosphatase(ALPase) 경우는 p-nitrophenylphosphate 외에도 inositol phosphate를 가수분해하는 특성을 나타냈다. ACPase는 50 mM acetate buffer, pH 5.2에서 최고 활성도를, ALPase 경우는 $Mg^{2+}$ 존재하의 50 mM Hepes buffer, pH 7.8에서 최고의 활성도를 나타냈다. 여러 무기이온의 영향을 보았을 때, ACPase는 $Na^+$와 $K^+$ 및 $Mg^+$ 등에 의해 전혀 영향을 받지 않았으나, ALPase 경우는 $Na^+$ 50 mM과 $K^+$ 100 mM 에서 약 3.4배의 활성화를 나타냈고, 한편 0.2mM $Mg^{2+}$에 의해서는 약 5배의 활성도 증가를 보였으며, $Ca^{2+}$에 의해서는 저해현상과 동시에 $Mg^{2+}$에 대해 경쟁적 저해를 나타냈다. ALPase에 대한 ouabain 및 L-phenylalanine의 영향을 보았을 때, ouabain은 별 영향이 없었으나, L-phenylalanine의 경우는 약간의 활성화를 나타냈다.

생쥐 간의 Triacylglycerol 생합성에 있어서 Palmitoylcarnitine의 지방산 공여체로서의 역할

이윤경,정진성,조기승,Lee, Youn-Kyung,Chung, Jin-Sung,Cho, Key-Seung 생화학분자생물학회 1986 한국생화학회지 Vol.19 No.3

$^{14}C$-Palmitoylcarnitine을 생쥐 간 균질물과 반응시킨 결과 1시간 후 33%, 3시간 후에 51%, 6시간 후에 최고 61%의 가수분해를 나타냄으로서, 동물체의 간이 acylcarnitine의 중요한 대사부위 임을 나타내 주었다. $^{14}C$-Palmitoylcarnitine ($^{14}C$-pal. carn)에 의한 $^{14}C$-triacylglycerol ($^{14}C$-TG)의 생합성은 0.1 M tris-HCl buffer, pH 7.4 및 반응온도 $20^{\circ}C$에서 각각 최고의 합성율을 나타냈고, ATP, coenzyme A (CoASH), $Ca^{2+}$ 및 $Mg^{2+}$의 cofactor 등은 triacylglycerol 생 합성계에 전혀 영향을 끼치지 않았으며, 이들은 phospholipid 생성계를 활성화시키는 것으로 나타났다. 동일 조건하에서 (U-$^{14}C$)-palmitic acid에 의한 중성지 질의 생합성을 비교하여 본 결과, 반응온도는 $20^{\circ}C$가 적정온도였고, 이 반응계는 ATP, CoASH 및 $Mg^{2+}$의 cofactor를 필요로 했는데 반응시간에 따라 차이를 보여주었다. 즉, 30분 반응에서는 cofactor 존재하에서 $^{14}C$-TG 생성이 증가를 보였으나, 3시간 반응에서는 cofactor가 존재하지 않은 대조구보다 $^{14}C$-phospholipids 생성이 증가함을 나타냈다. 간 균질물의 여러 분획에 있어서 $^{14}C$-pal. carn에 의한 $^{14}C$-TG의 생성을 비교해 본 결과, microsomal cytosol 분획에서 가장 높은 triacylglycerol와 diacylglycerol의 생성율을 보였고, 다음이 mitochondria 분획, nuclei와 cell debris 분획 순이었다. 이상의 결과로 보아 palmitoylcarnitine은 microsome에서 cofactor의 도움 없이 직접 acyl group을 이전시켜 중성지질을 생성하는 것을 확인할 수 있었다. It was confirmed that the important metabolic site of acylcarnitine was liver in mamals from the results of its hydrolysis, in which percent of hydrolysis was 33%, 51 %, and 61% from incubation for 1 h, 3 h, and 6 h, respectively. In the triacylglycerol biosynthesis from (U-$^{14}C$)-palmitolyl-DL-carnitine, the optimum conditions were obtained in 0.1 M tris-HCl buffer, pH 7.4 and $20^{\circ}C$ of incubation temperature. The effect of cofactors, such as $Ca^{2+}$, $Mg^{2+}$, ATP, and coenzyme A reduced the formation of triacylglycerol, rather increased the formation of phospholipid. This result showed that triacylglycerol synthesis from palmitolycarnitine did not need any cofactors. The comparison of the triacylglycerol biosynthesis from (U-$^{14}C$)-palmitic acid with that of (U-$^{14}C$)-palmitoyl-DL-carnitine showed the same optimum conditons in pH and incubation temperature. But in cofactors effect, tracylglycerol synthesis from $^{14}C$-palmitic acid was stimulated in the presence of ATP, CoASH, and $Mg^{2+}$ in 30 min incubation when it was compared with or without of cofactors. When the incubation period was prolonged to 3 h, triacylglycerol synthesis was reduced and, on the other hand, phospholipid synthesis was increased significantly more than 6 times. With the results from the different cell fractions, the highest triacylglycerol biosynthesis was prepresented with microsomal cytosol fraction and next was in order of mitochondrial fraction and nuclei cell debris fraction. As conclusion, firstly, it could be postulated that the direct mobilization of acyl group from palmitoylcarnitine to monoacylglycerol and diacylglycerol resulted triacylglycerol synthesis. Secondly, free fatty acid from hydrolysis of palmitoylcarnitine might from acyl CoA in the presence of ATP and CoASH, and continued the sequencial reactions with diacylglycerol and with Iysophospholipid to form the triacylglycerol and phospholipid, respectively.

Ferric ion ( Fe3+ ) 에 의한 사람혈청 Acid Phopshatase 의 활성화

이종호,신현수,조기승 ( Jong Ho Lee,Hyun Soo Shin,Key Seung Cho ) 생화학분자생물학회 1985 BMB Reports Vol.18 No.2

The acid phosphatase (EC 3.1.3.2.) of human serum has shown to have a maximum activity with 0.1 M acetate buffer at pH 5.0 and had an appreciable activity at a low of 0℃ and also a stable character even with a little high temperature of 50℃. Among several heavy metal ions tested, Na^+, K^+, Ca^(2+), Hg^(2+) and Cd^(2+) did not affected significantly, but Cu^(2+) and Fe^(2+) inhibited enzyme activity seriously. On the other hand, addition of Fe^(3+) to incubation mixture, it stimulated the acid phsophatase more than 2.5 times. EDTA had no effect on the enzyme at all, and rather restored some extent of the inhibitory effect by Fe^(2+). From this result, affinity of Cu^(2+) to enzyme active site was stronger than that of Fe^(2+). In the case of Fe^(3+) stimulation, the enzyme activity was increased more than 3.5 times when Fe^(3+) was preincubated with EDTA for 1 min before addition of enzyme and substrate. And also preincubation of enzyme with Fe^(3+) before addition of EDTA and substrate, it showed a little reduced activity but still high stimulation when it compared with control group.

사람 적혈구에 있어서 극성 대사물질과 막 구성분의 Uptake에 관한 1-Palmitoyllysolecithin과 인삼 Saponin의 영향

정진성,이종호,조기승,주충노,Chung, Jin-Sung,Lee, Jong-Ho,Cho, Key-Seung,Joo, Chung-No 생화학분자생물학회 1986 한국생화학회지 Vol.19 No.2

사람 적혈구에서 [$^{14}C$]-alanine, [$^{14}C$]-glucose, [$^{14}C$]-cholesterol 및 [$^{14}C$]-phosphatidylethanolamine의 흡수를 lysolecithin과 saponin 존재하에서 실험하여 본 결과 다음과 같은 결과를 얻었다. 적혈구를 lysolecithin으로 미리 처리시켰을 때, 상기 물질들의 uptake가 alanine의 경우 최고 111%, glucose는 43%, cholesterol은 48%, phosphatidylethanolamine은 17%의 상승율을 보였고, saponin의 처리에 의해서는 각각 408%, 70%, 28% 및 10%의 상승율을 나타냈다. 두 lytic agent에 의한 상승율은 각각의 최적 농도에서 비교해보면 lysolecithin은 saponin 경우보다 막성분인 cholesterol이나 phosphatidylethanolamine의 uptake에 더 영향을 끼쳤고, 한편 saponin은 alanine과 glucose와 같은 polar metabolite의 uptake에 더 영향을 주는 것으로 확인되었다. The effects of lysolecithin and ginseng saponin on the uptake of [$^{14}C$]-alanine, [$^{14}C$]-glucose, [$^{14}C$]-cholesterol, and [$^{14}C$]-phosphatidylethanolamine to human erythrocytes in the various conditions were as follows. When the human erythrocytes pretreated in the presence of low lytic amount of lysolecithin, the uptake of such polar metabolites and membrane components was enhanced up to [$^{14}C$]-alanine 111%, [$^{14}C$]-glucose 43%, [$^{14}C$]-cholesterol 48%, and [$^{14}C$]-phosphatidylethanolamine 17%, In case of saponin pretreatment, the uptakes of such substances were increased to 408%, 70%, 28%, and 10%, respectively. In comparison with both lytic surfactants under the optimum concentration, lysolecithin was more effective to the uptake of membrane components, cholesterol and phosphatidylethanolamine. On the other hand, saponin was more potent to the polar metabolite uptake into the erythrocytes.

Ferric ion($Fe^{3+}$)에 의한 사람 혈청 Acid Phosphatase의 활성화

이종호,신현수,조기승,Lee, Jong-Ho,Shin, Hyun-Soo,Cho, Key-Seung 생화학분자생물학회 1985 한국생화학회지 Vol.18 No.2

사람혈청의 Acid phosphatase(EC 3.1.3.2.)는 0.1 M acetate buffer, pH 5.0에서 최고 활성도를 나타냈다. 이 효소의 온도 영향을 보면, $0^{\circ}C$에서도 상당한 활성도를 보였고, $10^{\circ}C$까지는 약간 감소하나 온도증가에 따라 $50^{\circ}C$까지 계속 상승함을 보여 줌으로서 고온에서도 상당히 안정함을 나타냈다. 여러 금속 ion에 대한 영향을 보면, $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Hg^{2+}$ 및 $Cd^{2+}$ 등에 의해서는 별로 영향을 받지 않으나, $Cu^{2+}$ 와 $Fe^{2+}$에 의해서는 심한 저해 현상을 보였다. 한편 배양액에 $Fe^{3+}$를 가했을 때 ACPase는 대조구보다 2.5배 이상 활성화됨을 보였는데, EDTA와의 여러 반응 조건에 따라 보여준 결과는 매우 중요한 의마를 냐타내 주었다. EDTA는 ACPase에 전혀 영향을 끼치지 않았으며, $Cu^{2+}$ 와 $Fe^{2+}$의 저해 효과에 대한 EDTA의 영향을 보면, $Cu^{2+}$에 의한 효소저해는 재생시키지 않았으나 $Fe^{2+}$에 의한 저해는 60%정도 재생시킴으로서 $Cu^{2+}$이 효소의 활성부위와 견고하게 binding됨을 알 수 있게 하였다. Ferric ion($Fe^{3+}$)의 ACPase 활성화에 있어서, EDTA를 $Fe^{3+}$과 1분간 preincubation시켰을때 3.5배 이상 효소활성도를 촉진시켰으며, 효소를 $Fe^{3+}$과 1분간 preincubation시킨후 EDTA를 가했을때는 이보다 약간 감소되는 결과를 보였으나, 효소활성을 대조구보다 상당히 활성화시킴을 나타냈다. The acid phosphatase (EC 3.1.3.2.) of human serum has shown to have a maximum activity with 0.1 M acetate buffer at pH 5.0 and had an appreciable activity at a low of $0^{\circ}C$ and also a stable character even with a little high temperature of $50^{\circ}C$ Among several heavy metal ions tested, $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Hg^{2+}$ and $Cd^{2+}$ did not affected significantly, but $Cu^{2+}$ and $Fe^{2+}$ inhibited enzyme activity seriously. On the other hand, addition of $Fe^{3+}$ to incubation mixture, it stimulated the acid phsophatase more than 2.5 times. EDTA had no effect on the enzyme at all, and rather restored some extent of the inhibitory effect by $Fe^{2+}$ From this result, affinity of $Cu^{2+}$ to enzyme active site was stronger than that of $Fe^{2+}$. In the case of $Fe^{3+}$ stimulation, the enzyme activity was increased more than 3.5 times when $Fe^{3+}$ was preincubated with EDTA for 1 min before addition of enzyme and substrate. And also preincubation of enzyme with $Fe^{3+}$ before addition of EDTA and substrate, it showed a little reduced activity but still high stimulation when it compared with control group.

적혈구 막에 관한 연구 ( 1 ) Palmityoyl Carnitine 에 의한 소 적혈구 막의 용해

이강순,장정순,조기승,이강석 ( Kang Soon Rhee,Chung Soon Chang,Key Seung Cho,Kang Suk Lee ) 생화학분자생물학회 1975 BMB Reports Vol.8 No.1

The mechanism of solubilization of the ox-erythrocyte membrane was investigated with palmitoyl carnitine. When the membrane was treated with palmitoyl carnitine, the membrane protein, phospholipids and cholesterol were completely solubilized. It was confirmed that lipids were not liberated from membrane lipoprotein and not form micelles with palmitoyl carnitine. As a consequence, membrane was solubilized as a form of lipoprotein. In the present study, the results indicated that the erythrocyte membrane was solubilized by involvement of ionic and hydrophobic interaction of membrane lipoprotein with palmitoyl carnitine. The solubility of erythrocyte membrane depended upon the degree of the hydrophobic binding with palmitoyl carnitine. In the complete solubilized membrane, the activities of ATPase (Na^+, K^+-dependent) and glucose-6-phosphatase were not affected or rather slightly increased of 28% and 56% as compared with intact membrane, respectively. The effect of pH on solubilized membrane protein showed that 92% of protein was precipitated at pH 5.0. In polyacrylamide gel electrophoresis with Tris-glycine buffer, pH 8.3, solubilized membrane protein was separated into 8 bands with molecular weight ranged from 450,000 to 70,000.

생쥐뇌 세포질 분획의 Acid 및 Alkaline Phosphatase 의 특성 비교 연구

강창균,이영식,조기승 ( Chang Gyun Kang,Young Seek Lee,Key Seung Cho ) 생화학분자생물학회 1990 BMB Reports Vol.23 No.3

Acid and alkaline phosphatases from mouse brain cytosol fraction were separated and partially purified with 91 and 15 folds, respectively, by DEAE-cellulose column chromatography and Sephadex G-150 gel chromatography. Acid phosphatase (ACPase, EC 3.1.3.2) showed substrate specificity only to p-nitrophenylphosphate among the several substrates tried, such as, adenosine-3`-monophosphate (3`-AMP), adenosine-5`-monophosphate (5`-AMP), adenosine-5`-triphosphate (5`-ATP), glucose-6-phosphate (G-6-P), inositol-1`-monophosphate (IP), inositol-1,4,5-triphosphate (IP₃ and p-nitrophenylphosphate (PNPP). On the other hand, alkaline phosphatase (ALPase, EC 3.1.3.1) showed to active to PNPP and IP substrates among them. ACPase and ALPase showed the maximum enzyme activities at pH 5.2 with 50 mM acetate buffer and at pH 7.8 with 50 mM Hepes buffer in the presence of Mg^(2+), respectively. In the effect of Na^+ and K^+ on both ACPase and ALPase, these ions had no effect at all on ACPase, but 50 mM Na^+ and 100 mM K^+ showed maximum activation on ALPase by 3.4 times. Divalent cations,Ca^(2+) and Mg^(2+) showed no effect at all on ACPase, but 0.2 mM Mg^(2+) stimulated ALPase significantly about 5 times. On the other hand, Ca^(2+) represented competitive inhibition to Mg^(2+) effect on ALPase. Ouabain had no effect at all, but L-phenylalanine showed a minor stimulation on ALPase.