• 약학회지
• /
• 제44권2호
• /
• pp.197-203
• /
• 2000

The enzymatic properties of $\beta$-galactosidases from Aspergillus oryzae, bovine liver and Saccharomyces pragilis have been studied using enzyme-linked lectin assay based on the RC $A_{120}$ and BS-II lectins which specifically bind to terminal galactose and GlcNAc residue, respectively. Asialofetuin, a monomeric glycoprotein with approximately 48 kDa in molecular weight, was used as a substrate. This glycoprotein contains three N-linked triantennary complex type carbohydrate chains with each of which terminating in Ga1$\beta$P1 longrightarrow4G1cNAc (74%). Their optimal pHs were 3.5 and 6.5 (A. oryzae), and 3.5~5.5 (bovine liver and S. fragilis) at 37$^{\circ}C$ during 24 hrs, and the effective concentrations were 0.9, 2.9, and 1.7 mg/ml, respectively The enzyme from A oryzae requires 100 mM N $a^{+}$ or $K^{+}$, while the enzyme from bovine liver requires $Ba^{2+}$ for activity. However all of the three $\beta$-galactosidases were inactivated by SDS and C $u^{2+}$. These results indicate that the hydrolysis of glycoprotein such as asialofetuin depends on the reaction conditions of $\beta$-galactosidases and some metal ions. ions.

• Journal of Pharmaceutical Investigation
• /
• 제24권4호
• /
• pp.217-225
• /
• 1994

With the purpose of improving the therapeutic index of $[^3H]$ acyclovir (ACV) in the treatment of chronic hepatitis B infection, asialofetuin (AF) which after selective interaction with Ashwell's receptor specifically enters into hepatocytes, was chosen as a carrier system for hepatic targeting. This drug was first converted to its monophosphate (ACVMP), which was subsequently activated by water soluble carbodiimide to conjugate with ${\varepsilon}-NH_2$ groups of Iysine residues of AF. The molar ratio of ACVMP to AF in the conjugate was 3.9. In rats, elimination of ACVMP-AF conjugate after i.v. injection showed two phase elimination kinetics. Initial apparent elimination rate constant in rats was $0.191\;min^{-1}$ which was greater than that of ACV. The elimination rate constant from terminal phase was $0.021\;min^{-1}$. Area under the total radioactivities versus time curve was found to be several times larger in liver than in other organs (spleen, intestine, lung and kidney) after i.v. administration of the conjugate labelled in the drug moiety. The above results suggested that ACVMP-AF conjugate was rapidly taken up by hepatocytes and could be a useful hepatic targeting system.

• BMB Reports
• /
• 제28권1호
• /
• pp.6-11
• /
• 1995

A new lectin, named TRA, was purified from Trichosanthes kirilowii root by acid-treated Sepharose 6B, Mono-Q, and TSK-gel 3000SW column sequential chromatography. The lectin appeared homogeneous by native gel electrophoresis at pH 4.3 and gave two protein bands of Mr=31 and 28 kDa by SDS-PAGE. The N-terminal amino acid sequences of the polypeptides of TRA have not been reported in amino acid sequences of the lectins. TRA lectin formed a precipitate with asialofetuin, neuraminidase-treated fetuin. A sugar inhibition assay indicated that N-acetyl-D-galactosamine, among the monosaccharides tested, was the most potent inhibitor of TRA-induced hemagglutination. Asialofetuin showed a 260-times stronger inhibitory activity than N-acetyl-D-galactosamine. TRA lectin also showed agglutination with normal leukocytes and lymphoma cells, but not with premature hemopoietic cells. These results suggest that TRA is a novel plant lectin.

• Archives of Pharmacal Research
• /
• 제23권6호
• /
• pp.592-598
• /
• 2000

A lectin (agglutinin, VCA) from Korean mistletoe (Viscum album L. coloratum) was isolated by affinity chromatograpy on a asialofetuin-Sepharose 4B. The molecular weights of A- and B-chains of VCA were different from those of VAAS. The VCA recognized the antibody of VAAs in the Western blot analysis and ELLA system. We also investigated the synergistic effects of the components in mistletoe by dividing the extract into different molecular weight fractions.

• Journal of Pharmaceutical Investigation
• /
• 제27권1호
• /
• pp.1-10
• /
• 1997

For the purpose of improving the chemotherapeutic index of acyclovir(ACV), it was conjugated with asialofetuin(AF), which has been reported to enter into hepatocytes. When $[H^3]$ acyclovir in itself or its conjugate were administered to rats, the latter was taken up more selectively by the liver than any other tissues. The stability of ACVMP-AF conjugate in phosphate buffer (pH 5.0) and rat liver homogenate showed a pseudo-first order profile. ACVMP-AF, however, was relatively stable in pH7.4 phosphate buffer and rat plasma. The conjugate was added to the isolated rat hepatocyte and cellular uptake was monitored by scintillation counting for up to 6 hours at $37^{\circ}C$. Hepatocytes incubated with the conjugate exhibited radioactivities significantly enhanced over control levels dose-dependently, i.e., a 3-40 fold increase in radioactivities was observed over controls at the conjugate concentrations of $0.1-10\;{\mu}g/ml$. The AUQ in the liver, kidney, spleen, intestine and lung was higher in treatment with ACVMP-AF than that in treatment with ACV. In treatment with ACVMP-AF, the weighted-average overall drug targeting efficiency(Te) for the liver was higher than in treatment with ACV(57.00 vs 13.31 %), and the weighted-average tissue exposure(Re) was 5.03 for the liver. These results indicated that ACVMP-AF conjugate was rapidly taken up by hepatocytes and could be an efficient and selective hepatic targeting system.

• BMB Reports
• /
• 제38권5호
• /
• pp.526-532
• /
• 2005

A lectin with in-vitro anticancer activity against established human cancer cell lines has been purified by affinity chromatography on asialofetuin-linked amino activated silica beads from the tubers of Arisaema tortuosum, popularly known as Himalayan Cobra lily, a monocot plant from the family Araceae. The bound Arisaema tortuosum lectin (ATL) was eluted with glycine-HCl buffer, pH 2.5. ATL was effectively inhibited by asialofetuin, a complex desialylated serum glycoprotein as well as by N-acetyl-D-lactosamine, a disaccharide. It gave a single band corresponding to a subunit molecular weight of 13.5 kDa in SDS-PAGE, pH 8.8 both under reducing and non reducing conditions. When subjected to gel-filtration on Biogel P-200, it was found to have a molecular weight of 54 kDa, suggesting a homotetramer structure, in which individual polypeptides are not bound to each other with disulfide bonds. ATL is a glycoprotein with 0.9% carbohydrate content, stable up to $55^{\circ}C$ and at pH 2 to 10. The lectin had no requirement for divalent metal ions i.e. $Ca^{2+}$ and $Mn^{2+}$ for its activity. However, as reported for other monocot lectins, ATL gave multiple bands in isoelectric focusing and Native PAGE, pH 8.3. The lectin was found to inhibit in vitro proliferation of human cancer cell lines HT29, SiHa and OVCAR-5.

• 한국균학회지
• /
• 제23권1호통권72호
• /
• pp.46-52
• /
• 1995

화경버섯의 자실체로부터 PAGE로 한 렉틴을 정제하고, LJAP(Lampteromyces japonicus antibacterial protein)라 이름 붙였다. LJAP는 17-kDa의 서브유닛트가 모여서 된 백 kDa이 넘는 회합 단백질이였다. 이 단백질은 아미노산 분석결과 세린, 글리신, 산성 아미노산의 함량이 높았다. LJAP는 대장균중 특히 JM 109, K 12, HB 101, JW 380에 대한 항세균작용이 뛰어났다. 한편, 항세균활성은 당단백질인 asialofetuin에 의하여 크게 억제되었다. 본 당단백질은 화경버섯에서 처음으로 얻어진 항세균활성과 적혈구 응집활성을 가진 렉틴이다.

• BMB Reports
• /
• 제39권4호
• /
• pp.432-440
• /
• 2006

A tuber lectin from Arisaema jacquemontii Blume belonging to family Araceae was purified by employing a single step affinity chromatography using column of asialofetuin-linked amino activated silica beads and the bound lectin was eluted with 100 mM glycine-HCl buffer pH 2.5. The purified A. jacquemontii lectin (AJL) showed a single protein band with an apparent molecular mass of 13.4 kDa when submitted to SDS-polyacrylamide gel electrophoresis under reducing as well as non-reducing conditions. The native molecular mass of AJL determined by gel filtration on a Biogel P-200 column was 52 kDa and its carbohydrate content was estimated to be 3.40%. Thus AJL is a tetrameric glycoprotein. The purified lectin agglutinated erythrocytes from rabbit but not from human. Its activity was not inhibited by any of the mono- and disaccharides tested except N-acetyl-D-lactosamine having minimal inhibitory sugar concentration (MIC) 25 mM. Among the glycoproteins tested only asialofetuin was found to be inhibitory (MIC $125\;{\mu}g/mL$). A single band was obtained in native PAGE at pH 4.5 while PAGE at pH 8.3 showed two bands. Isoelectric focusing of AJL gave multiple bands in the pI range of 4.6-5.5. When incorporated in artificial diet AJL significantly affected the development of Bactrocera cucurbitae (Coquillett) larvae indicating the possibility of using this lectin in a biotechnological strategy for insect management of cucurbits. Larvae fed on artificial diet containing sub-lethal dose of AJL showed a significant decrease in acid phosphatase and alkaline phosphatase activity while esterase activity markedly increased as compared to larvae fed on diet without lectin. Out of various human cancer cell lines employed in sulphorhodamine B (SRB) assay, this lectin was found to have appreciable inhibitory effect on the in vitro proliferation of HCT-15, HOP-62, SW-620, HT-29, IMR-32, SKOV-3, Colo-205, PC-3, HEP-2 and A-549 cancer cell lines by 82, 77, 73, 70, 41, 41, 37, 29, 21 and 21% respectively.

• Journal of Pharmaceutical Investigation
• /
• 제22권2호
• /
• pp.155-161
• /
• 1992

Although glycosylated liposomes have attracted much attention as targeting delivery systems (DDS) of drugs to specific organs which have glycoside receptors, physical instability of liposomes greatly limits their practical application. In this case, proliposomes might be a potential answer to solve this problem. Utilizing the proliposomes as tageting DDS has been a goal of our series of works; we have tried to develop DDS which form liposomes uppon adding water and can deliver drugs to specific target organs/cells such as hepatocytes. In this paper, preparation of glycosylated liposomes and binding of the liposomes with lectin (agglutinin RCA 120) was studied. Asialoletuin (AF) was selected as a model compound which has galactose terminal and is favorable for binding with galactose receptor on the surface of hepatocytes. AF was obtained by splitting the terminal N-acetylneuraminic acid (NANA) of fetuin. Small unilamellar AF-liposomes were prepared by mixing aqueous solution of AF-palmitate with thin film of phosphatidyl choline and cholesterol (30:10 w/w) formed on the innersurface of the round bottomed flask. They were successively extruded through polycarbonate membranes (0.45 mm). Palmitoyl-AF not incorporated into the liposomal bilayer was separated from liposomes by a Sepharose 4B column equilibrated with 10 mM Tris-HCI buffered saline. Lectin (agglutinin RCA 120) was added to the suspension of AF-liposomes and incubated at $37^{\circ}C$ for 2 hr. After centrifugation, the unbound lectin in the supernatant was assayed for protein. The binding of the lectin to AF-liposomes (AF content 2.8 nmole) at $37^{\circ}C$ was linear at least upto 35 mg of lectin indicating high affinity association of the lectin to AF molecules of the liposomes.

• Applied Biological Chemistry
• /
• 제42권4호
• /
• pp.304-309
• /
• 1999

식용버섯인 팽이버섯(Flammulina velutipes)으로부터 적혈구 응집능력을 갖는 렉틴(flammulina velutipes lectin, FVL) FVL-1과 FVL-2을 정제하였다. FVL-1과 FVL-2의 분자량은 각각 10.6 kDa과 37 kDa으로 추정되었다. FVL-2는 사람적혈구의 경우 모든 혈액형에서 응집현상을 나타내었으나, FVL-1은 O형의 적혈구에 대하여 높은 상대활성도를 나타내었다. 렉틴의 hemagglutination inhibition test 결과 FVL-1과 FVL-2는 fetuin, bovine submaxillary mucin, asialofetuin, porcine stomach mucin에 의해 적혈구 응집력이 저해되었다. FVL-1은 1.56 mM $Cu^{2+}$에서 적혈구 응집력이 저해되었으며, $Mg^{2+}$, $Mn^{2+}$, $Ca^{2+}$, $Fe^{2+}$ 등에서도 저해되었다. 반면 FVL-2는 금속 이온에 대한 저해가 나타나지 않았다. pH 안정성에 있어서 FVL-1은 pH $5{\sim}11$에서 안정하였으며, FVL-2는 pH 4까지의 범위에서 안정하였다. 온도 안정성에 있어서는 FVL-1과 FVL-2 각각 $55^{\circ}C$, $45^{\circ}C$까지 안정하였다. FVL-1은 단백질이었으며 FVL-2는 당 단백질이었다.