The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Masao Iwamori - One of the best experts on this subject based on the ideXlab platform.
-
involvement of the c terminal tail of Arthrobacter Ureafaciens sialidase isoenzyme m in cleavage of the internal sialic acid of ganglioside gm1
Journal of Biochemistry, 2005Co-Authors: Masao Iwamori, Yasuhiro Ohta, Takeo Kaido, Yuriko Iwamori, Kentaro Tsukamoto, Shunji KozakiAbstract:: Arthrobacter Ureafaciens sialidase comprises four isoenzymes, L, M1, M2 and S, of which L, M1, and M2, but not S, have the unique ability to cleave GM1 ganglioside, but the hydrolysis of GM3 and colominic acid by S occurs at a higher rate than that by L, M1 and M2. Since the N-terminal amino acid sequences of L, M1, M2 and S were shown to be identical on protein sequencing, they were suggested to have arisen from the same protein through truncation at different C-terminal sites. A DNA segment containing an open reading frame was cloned from a genomic library, and the structural gene was found to comprise 2,970 bp encoding a protein of 990 amino acids including a signal peptide at the N-terminus, a conserved FYRIP-region and four Asp boxes. The molecular weights of the isoenzymes determined by MALDI-TOFMS revealed that L, M1, M2 and S should comprise amino acids 39-773, 39-653, 39-655 and 39-528, respectively. In fact, recombinant enzymes M2 and S prepared in Escherichia coli exhibited identical substrate specificities toward gangliosides as those of the purified enzymes. Consequently, the C-terminal tail of isoenzyme M2 might be involved in the hydrolysis of the internal sialic acid of GM1.
-
Arthrobacter Ureafaciens sialidase isoenzymes l m1 and m2 cleave fucosyl gm1
Glycoconjugate Journal, 1997Co-Authors: Masao Iwamori, Yasuhiro Ohta, Yoshihiro Uchida, Yoji TsukadaAbstract:Among bacterial, fungal and viral sialidases, the sialidase from Arthrobacter Ureafaciens has the unique property of cleaving sialic acids linked to the internal galactose of gangliotetraose. In this study, we examined the ability to cleave the internal sialic acids of GM1 and fucosyl GM1 of sialidases from several bacterial and fungal origins, including Clostridium perfringens and Vibrio cholerae. We found that A. Ureafaciens sialidase could liberate the sialic acid of GM1 at the highest rate, and was the only enzyme which could cleave fucosyl GM1 among the sialidases examined.
-
Arthrobacter Ureafaciens sialidase isoenzymes, L, M1 and M2, cleave fucosyl GM1
Glycoconjugate Journal, 1997Co-Authors: Masao Iwamori, Yasuhiro Ohta, Yoshihiro Uchida, Yoji TsukadaAbstract:Among bacterial, fungal and viral sialidases, the sialidase from Arthrobacter Ureafaciens has the unique property of cleaving sialic acids linked to the internal galactose of gangliotetraose. In this study, we examined the ability to cleave the internal sialic acids of GM1 and fucosyl GM1 of sialidases from several bacterial and fungal origins, including Clostridium perfringens and Vibrio cholerae. We found that A. Ureafaciens sialidase could liberate the sialic acid of GM1 at the highest rate, and was the only enzyme which could cleave fucosyl GM1 among the sialidases examined. The affinity-purified sialidase derived from the culture medium of A. Ureafaciens was comprised of four isoenzymes with different molecular weights and isoelectric points, the isoenzymes that cleaved fucosyl GM1 being L (88 kDa, pI 5.0), M1 (66 kDa, pI 6.2) and M2 (66 kDa, pI 5.5), but not S (52 kDa, pI 6.2) which showed the highest specific activity toward colominic acid among the four isoenzymes. Abbreviations: SA, sialic acid; PBS, phosphate-buffered saline; PVP, polyvinylpyrrolidone; FABMS, fast atom bombardment mass spectrometry; Galβint, internal galactose of Gg4Cer; Galβext, external galactose of Gg4Cer
Yasuhiro Ohta - One of the best experts on this subject based on the ideXlab platform.
-
involvement of the c terminal tail of Arthrobacter Ureafaciens sialidase isoenzyme m in cleavage of the internal sialic acid of ganglioside gm1
Journal of Biochemistry, 2005Co-Authors: Masao Iwamori, Yasuhiro Ohta, Takeo Kaido, Yuriko Iwamori, Kentaro Tsukamoto, Shunji KozakiAbstract:: Arthrobacter Ureafaciens sialidase comprises four isoenzymes, L, M1, M2 and S, of which L, M1, and M2, but not S, have the unique ability to cleave GM1 ganglioside, but the hydrolysis of GM3 and colominic acid by S occurs at a higher rate than that by L, M1 and M2. Since the N-terminal amino acid sequences of L, M1, M2 and S were shown to be identical on protein sequencing, they were suggested to have arisen from the same protein through truncation at different C-terminal sites. A DNA segment containing an open reading frame was cloned from a genomic library, and the structural gene was found to comprise 2,970 bp encoding a protein of 990 amino acids including a signal peptide at the N-terminus, a conserved FYRIP-region and four Asp boxes. The molecular weights of the isoenzymes determined by MALDI-TOFMS revealed that L, M1, M2 and S should comprise amino acids 39-773, 39-653, 39-655 and 39-528, respectively. In fact, recombinant enzymes M2 and S prepared in Escherichia coli exhibited identical substrate specificities toward gangliosides as those of the purified enzymes. Consequently, the C-terminal tail of isoenzyme M2 might be involved in the hydrolysis of the internal sialic acid of GM1.
-
Ganglioside GMia on the Cell Surface Is Involved in the Infection by Human Rotavirus KUN and MO Strains
Journal of Biochemistry, 1999Co-Authors: Osanmu Nakagomi, Yasuhiro Ohta, Makoto Kiso, Masami Mochizuki, Hideharu Ishida, Takashi Suzuki, Daisei Miyamoto, Kazuya I.p.j. Hidari, Yasuo SuzukiAbstract:: Rotavirus is the most common cause of severe gastroenteritis in infants and children worldwide. The cell attachment of most animal rotaviruses, which belong to the neuraminidase-sensitive strains, requires sialic acid residues on the host cell membranes. On the other hand, most human rotaviruses are classified as neuraminidase-insensitive strains. The involvement of gangliosides on the host cell surface in human rotavirus infection was investigated by immunostaining analysis of target cells, and by assaying the neutralization of infection by rotavirus and the blocking of target cellular receptors. In host cells (MA104 cells) pretreated with Arthrobacter Ureafaciens neuraminidase, which were still infected by human rotaviruses (KUN and MO strains), GM(3) was hydrolyzed markedly by the neuraminidase, while GM(1a) was not hydrolyzed at all. Infection by the rotaviruses was strongly inhibited by exogenous ganglioside GM(1a), but not GA(1). Infection was also inhibited by pretreatment of the MA104 cells with cholera toxin B-subunit, which specifically blocked ganglioside GM(1a) on the plasma membrane. The treatment of MA104 cells with the endoglycoceramidase attenuated human rotavirus infection. From these findings, we concluded that GM(1a) on the plasma membrane of the host cells was involved in the infection by human rotavirus KUN and MO strains.
-
Arthrobacter Ureafaciens sialidase isoenzymes l m1 and m2 cleave fucosyl gm1
Glycoconjugate Journal, 1997Co-Authors: Masao Iwamori, Yasuhiro Ohta, Yoshihiro Uchida, Yoji TsukadaAbstract:Among bacterial, fungal and viral sialidases, the sialidase from Arthrobacter Ureafaciens has the unique property of cleaving sialic acids linked to the internal galactose of gangliotetraose. In this study, we examined the ability to cleave the internal sialic acids of GM1 and fucosyl GM1 of sialidases from several bacterial and fungal origins, including Clostridium perfringens and Vibrio cholerae. We found that A. Ureafaciens sialidase could liberate the sialic acid of GM1 at the highest rate, and was the only enzyme which could cleave fucosyl GM1 among the sialidases examined.
-
Arthrobacter Ureafaciens sialidase isoenzymes, L, M1 and M2, cleave fucosyl GM1
Glycoconjugate Journal, 1997Co-Authors: Masao Iwamori, Yasuhiro Ohta, Yoshihiro Uchida, Yoji TsukadaAbstract:Among bacterial, fungal and viral sialidases, the sialidase from Arthrobacter Ureafaciens has the unique property of cleaving sialic acids linked to the internal galactose of gangliotetraose. In this study, we examined the ability to cleave the internal sialic acids of GM1 and fucosyl GM1 of sialidases from several bacterial and fungal origins, including Clostridium perfringens and Vibrio cholerae. We found that A. Ureafaciens sialidase could liberate the sialic acid of GM1 at the highest rate, and was the only enzyme which could cleave fucosyl GM1 among the sialidases examined. The affinity-purified sialidase derived from the culture medium of A. Ureafaciens was comprised of four isoenzymes with different molecular weights and isoelectric points, the isoenzymes that cleaved fucosyl GM1 being L (88 kDa, pI 5.0), M1 (66 kDa, pI 6.2) and M2 (66 kDa, pI 5.5), but not S (52 kDa, pI 6.2) which showed the highest specific activity toward colominic acid among the four isoenzymes. Abbreviations: SA, sialic acid; PBS, phosphate-buffered saline; PVP, polyvinylpyrrolidone; FABMS, fast atom bombardment mass spectrometry; Galβint, internal galactose of Gg4Cer; Galβext, external galactose of Gg4Cer
-
synthesis of sialyllactose from n acetylneuraminic acid and lactose by a neuraminidase from Arthrobacter Ureafaciens
Bioscience Biotechnology and Biochemistry, 1992Co-Authors: Isafumi Maru, Yasuhiro Ohta, Kaoru Okamoto, Shigeo Suzuki, Kazuaki Kakehi, Yoji TsukadaAbstract:Two sialyllactose isomers, NeuAcα2→6Galβ1→4Glc and Galβ1→4(NeuAcα2→6)Glc, were prepared by incubation of a concentrated solution of N-acetylneuraminic acid and lactose in the presence of a neuraminidase from Arthrobacter Ureafaciens. Each sialyllactose was isolated by a combination of ion-exchange chromatography and high performance liquid chromatography. The structure of each sialyllactose was identified by mass spectrometry, nuclear magnetic resonance spectrometry, and enzymatic analysis.
Yoji Tsukada - One of the best experts on this subject based on the ideXlab platform.
-
Arthrobacter Ureafaciens sialidase isoenzymes l m1 and m2 cleave fucosyl gm1
Glycoconjugate Journal, 1997Co-Authors: Masao Iwamori, Yasuhiro Ohta, Yoshihiro Uchida, Yoji TsukadaAbstract:Among bacterial, fungal and viral sialidases, the sialidase from Arthrobacter Ureafaciens has the unique property of cleaving sialic acids linked to the internal galactose of gangliotetraose. In this study, we examined the ability to cleave the internal sialic acids of GM1 and fucosyl GM1 of sialidases from several bacterial and fungal origins, including Clostridium perfringens and Vibrio cholerae. We found that A. Ureafaciens sialidase could liberate the sialic acid of GM1 at the highest rate, and was the only enzyme which could cleave fucosyl GM1 among the sialidases examined.
-
Arthrobacter Ureafaciens sialidase isoenzymes, L, M1 and M2, cleave fucosyl GM1
Glycoconjugate Journal, 1997Co-Authors: Masao Iwamori, Yasuhiro Ohta, Yoshihiro Uchida, Yoji TsukadaAbstract:Among bacterial, fungal and viral sialidases, the sialidase from Arthrobacter Ureafaciens has the unique property of cleaving sialic acids linked to the internal galactose of gangliotetraose. In this study, we examined the ability to cleave the internal sialic acids of GM1 and fucosyl GM1 of sialidases from several bacterial and fungal origins, including Clostridium perfringens and Vibrio cholerae. We found that A. Ureafaciens sialidase could liberate the sialic acid of GM1 at the highest rate, and was the only enzyme which could cleave fucosyl GM1 among the sialidases examined. The affinity-purified sialidase derived from the culture medium of A. Ureafaciens was comprised of four isoenzymes with different molecular weights and isoelectric points, the isoenzymes that cleaved fucosyl GM1 being L (88 kDa, pI 5.0), M1 (66 kDa, pI 6.2) and M2 (66 kDa, pI 5.5), but not S (52 kDa, pI 6.2) which showed the highest specific activity toward colominic acid among the four isoenzymes. Abbreviations: SA, sialic acid; PBS, phosphate-buffered saline; PVP, polyvinylpyrrolidone; FABMS, fast atom bombardment mass spectrometry; Galβint, internal galactose of Gg4Cer; Galβext, external galactose of Gg4Cer
-
synthesis of sialyllactose from n acetylneuraminic acid and lactose by a neuraminidase from Arthrobacter Ureafaciens
Bioscience Biotechnology and Biochemistry, 1992Co-Authors: Isafumi Maru, Yasuhiro Ohta, Kaoru Okamoto, Shigeo Suzuki, Kazuaki Kakehi, Yoji TsukadaAbstract:Two sialyllactose isomers, NeuAcα2→6Galβ1→4Glc and Galβ1→4(NeuAcα2→6)Glc, were prepared by incubation of a concentrated solution of N-acetylneuraminic acid and lactose in the presence of a neuraminidase from Arthrobacter Ureafaciens. Each sialyllactose was isolated by a combination of ion-exchange chromatography and high performance liquid chromatography. The structure of each sialyllactose was identified by mass spectrometry, nuclear magnetic resonance spectrometry, and enzymatic analysis.
Shunji Kozaki - One of the best experts on this subject based on the ideXlab platform.
-
involvement of the c terminal tail of Arthrobacter Ureafaciens sialidase isoenzyme m in cleavage of the internal sialic acid of ganglioside gm1
Journal of Biochemistry, 2005Co-Authors: Masao Iwamori, Yasuhiro Ohta, Takeo Kaido, Yuriko Iwamori, Kentaro Tsukamoto, Shunji KozakiAbstract:: Arthrobacter Ureafaciens sialidase comprises four isoenzymes, L, M1, M2 and S, of which L, M1, and M2, but not S, have the unique ability to cleave GM1 ganglioside, but the hydrolysis of GM3 and colominic acid by S occurs at a higher rate than that by L, M1 and M2. Since the N-terminal amino acid sequences of L, M1, M2 and S were shown to be identical on protein sequencing, they were suggested to have arisen from the same protein through truncation at different C-terminal sites. A DNA segment containing an open reading frame was cloned from a genomic library, and the structural gene was found to comprise 2,970 bp encoding a protein of 990 amino acids including a signal peptide at the N-terminus, a conserved FYRIP-region and four Asp boxes. The molecular weights of the isoenzymes determined by MALDI-TOFMS revealed that L, M1, M2 and S should comprise amino acids 39-773, 39-653, 39-655 and 39-528, respectively. In fact, recombinant enzymes M2 and S prepared in Escherichia coli exhibited identical substrate specificities toward gangliosides as those of the purified enzymes. Consequently, the C-terminal tail of isoenzyme M2 might be involved in the hydrolysis of the internal sialic acid of GM1.
Sonia Tomar - One of the best experts on this subject based on the ideXlab platform.
-
Investigation of substrate specificity of sialidases with membrane mimetic glycoconjugates
Glycoconjugate Journal, 2020Co-Authors: Sonia TomarAbstract:Sialidases or neuraminidases play important roles in various physiological and pathological processes by cleaving terminal sialic acids (Sias) (desialylation) from the glycans of both glycoproteins and glycolipids. To understand the biological significance of desialylation by sialidases, it is important to investigate enzyme specificity with native substrate in biological membrane of cells. Herein, we report a membrane-mimicking system with liposome ganglioside conjugates containing different lipids for evaluating substrate specificity of sialidase and the lipid effect on the enzyme activity. Briefly, liposomes of phosphatidylcholine (PC) and cholesterol with ganglioside (GM3 or GM1) along with different percentage of phosphatidylserine (PS) or phosphatidylethanolamine (PE) were prepared and characterized. Their desialylation profiles with Arthrobacter Ureafaciens (bacterial) sialidase and H1N1 (influenza viral) sialidase were quantified by HPLC method. A diversity of substrate preference was found for both bacterial and viral sialidase to the liposome ganglioside conjugate platform. The apparent K _m and V _max were dependent on the type of lipid. These results indicate that the intrinsic characteristics of the membrane-like system affect the sialidase specificity and activity. This biomimetic substrate provides a better tool for unravelling the substrate specificity and the biological function of sialidases and for screening of functional sialidase inhibitors as well.
