Genetic Recombination — Understanding the Mechanism : by H.L.K. Whitehouse Wiley; Chichester,New York, 1982

Interaction of peanut agglutinin with MeUmbβGalβ(1→3)GalNAc was followed with the stopped-flow technique. The mechanism is a simple bimolecular association with k₊ = 7.1 × 10³ M^?1. s^?1 and k_? = 0.24 s^?1 at 25°C. The very slow dissociation rate of the complex strongly supports earlier conclusions that the combining site of peanut agglutinin is complementary to the Galβ(1→3)GalNac structure.     

Galα1→4Gal-glycans are expressed on myofibrillar associated proteins

There is evidence that glycans carrying terminal galactose residues are differently expressed in the sarcoplasm of different muscle fiber types. In this study monoclonal antibodies directed against P blood group antigens P^k: Galα1–4Galβ1–4Glcβ- and P₁: Galα1–4Galβ1–4GlcNAcβ- were used to detect terminal α-galactosylated glycoconjugates on muscle proteins. Electrotransfer of proteins, extracted from human masseter and biceps muscles, to nitrocellulose after polyacrylamide gel electrophoresis (PAGE) and incubation with anti-P^k (CD77) consistently showed two bands with apparent molecular weights of 66 kDa and 64 kDa. In fresh frozen muscle sections from some humans there was endothelial reaction with anti-CD77 in capillaries, venules and veins but not in arterioles and arteries. In muscle samples from other humans there was no staining of endothelial cells. Formalin-fixed human muscle displayed a CD77 reaction with highest accumulation of reaction product at the periphery of the fibers. This may be explained by the presence of P^k glycoconjugates on intermediate filaments in muscle fibers. In preparations of cat masseter muscle proteins the antibodies against P₁P^k antigens reacted with a 170 kDa and a 55 kDa band while in preparations of cat biceps brachii only a 55 kDa band was reactive. The specificities of the antibodies were investigated by fluorescence-activated cell sorter (FACS), α- and β-galactosidase digestion and inhibitory sugars. This study indicates that glycans carrying Galα1–4Galβ1- epitopes are expressed on myofibrillar associated proteins.     

Structural studies of the carbohydrate moiety of human antithrombin III

Human antithrombin III contains four asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively released as radioactive oligosaccharides from the polypeptide portion by hydrazinolysis followed by N-acetylation and NaB³H₄ reduction. All of the oligosaccharides, thus obtained, contain N-acetylneuraminic acid. A same neutral nonaitol was released from all acidic oligosaccharides by sialidase treatment. By combination of the sequential exoglycosidase digestion and methylation analysis, their structures were elucidated as NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6-(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manαl → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, and NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc.     

The EPR spectrum of cytochrome b-563 in the cytocrhome bf complex from spinach: (1993) FEBS Letters 164, 71–74

Blood group H antigen with globo-series structure, reacting with the monoclonal antibody MBrl, was isolated and characterized from human blood group O erythrocytes. The structure was identified by methylation analysis, direct probe mass spectrometry, and ¹H-nuclear magnetic resonance spectroscopy as shown below: Fucαl → 2Galβl → 3GalNAcβl → 3Galαl → 4Galβl → 4Glcβl → 1Cer     

The hapten structure of a developmentally regulated glycolipid antigen (SSEA-1) isolated from human erythrocytes and adenocarcinoma: a preliminary note

Glycolipid antigen reacting to the monoclonal antibody directed to the developmentally regulated antigen SSEA-1 was isolated from human erythrocytes and colonic adenocarcinoma. The antigens have the Le^x (Galβl→4[Fucα]→3]GlcNAcβl→R) or Le^y (Fucαl→2Galβl→4[Fucαl→3]GlcNAcβl→R) structure at the termini of the branched polylactosaminolipid. In addition, a novel polyfucosyl structure locating exclusively at the internal GlcNAc was detected in the tumor antigen. The antibody reacts with a simple monovalent Le^x glycolipid (Galβl→4[Fucαl→3]GlcNAcβl→3Galβl→4Glcβl→Cer) previously isolated from colonic carcinoma when presented at a high density on liposomes. The antibody therefore may react to the bivalent or multivalent Le^x or Le^y structure.     

The asparagine-linked sugar chains of the glycoproteins in rat erythrocyte plasma membrane—Fractionation of oligosaccharides liberated by hydrazinolysis and structural studies of the neutral oligosaccharides

The asparagine-linked sugar chains of the plasma membrane glycoproteins of rat erythrocytes were released as oligosaccharides by hydrazinolysis and labeled by NaB³H₄ reduction. The radioactive oligosaccharides were separated into a neutral and at least four acidic fractions by paper electrophoresis. The neutral oligosaccharide fraction was separated into at least 11 peaks upon Bio-Gel P-4 column chromatography. Structural studies of them by sequential exoglycosidase digestion in combination with methylation analysis revealed that they were a mixture of three high mannose-type oligosaccharides and at least 11 complex type oligosaccharides with Manα1 → 6(Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4(±Fucα1 → 6)GlcNAc as their cores and Galβ1 → 4GlcNAc, Galβ1 → 3Galβ1 → 4GlcNAc, and various lengths of Galβ1 → 4GlcNAc repeating chains in their outer chain moieties. Most of the complex-type Oligosaccharides were biantennary, and the tri- and tetraantennary Oligosaccharides contain only the Galβ1 → 3Galβ1 → 4GlcNAc group in their outer chain moieties.     

Immunochemistry of the Lewis-blood-group system: Partial characterization of Lea-, Leb-, and H-type 1 (LedH)-blood-group active glycosphingolipids from human plasma

Four different H-type 1 (Le^dH) blood-group-active glycosphingolipids (Le^dH-I–IV) have been isolated from the plasma of blood-group O Le(a?b?) secretors. The agglutination of O Le(a?b?) erythrocytes from secretors by 50 μl of 4 hemagglutinating units of caprine anti-Le^dH (anti-H-type 1) serum was inhibited by 0.02 μg of each of all four glycolipids. No Le^a or Le^b activities or reaction against Ulex europaeus lectin could be found. Le^dH-I, -II, -III, and -IV at 0.05, 0.01, 0.01, and 0.02 μg each are sufficient for incubation in order to convert 9 × 10⁷ O Le(a?b?) erythrocytes from nonsecretors into H-type 1 (Le^dH)-positive cells. Structural analysis of the H-type 1 glycolipids was performed in comparison to that of Le^a- and Le^b-blood-group-active glycolipids from human plasma isolated previously: Gas chromatography of peracetylated alditols revealed sugar composition. Combined gas chromatography-mass spectrometry established the glycosidic linkages. Together with the results obtained by direct inlet mass spectrometry of permethylated glycosphingolipids and by 360-MHz ¹H nuclear magnetic resonance spectroscopy (Egge, H., and Hanfland, P., 1981, Arch. Biochem. Biophys., 210, 396–404; Dabrowski, J., Hanfland, P., Egge, H., and Dabrowski, U., 1981, Arch. Biochem. Biophys., 210, 405–411) the complete structures of the oligosaccharide chains of the Le^a-, Le^b-, and H-type 1-active glycolipids were established: Galβ1 → 3GlcNAc(4 ← 1αFuc)β1 → 3Galβ1 → 4Glcβ1 → 1 Cer for the Le^a antigens; Fucα1 → 2Galβ1 → 3GlcNAc(4 ← 1αFuc)β1 → 3Galβ1 → 4Glcβ1 → 1 Cer for the Le^b antigens; and Fucα1 → 2Galβ1 → 3GlcNAcβ1 → 3Galβ1 → 4Glcβ1 → 1 Cer for the H-type 1 (Le^dH) glycolipids. The diverse antigens of the same blood-group specificity obviously differ from one another in their lipid residue. In addition, plasmatic neolactotetraosylceramide could be identified, differing from that of human erythrocytes by a slower migration behavior in thin-layer chromatography.     

Specificity in the enzymic transfer of sialic acid to the oligosaccharide branches of BI- and triantennary glycopeptides of α1-acid glycoprotein

Partial $\text{in}\text{vitro}$ sialylation of biantennary and triantennary glycopeptides of α₁-acid glycoprotein using colostrum β-galactosideα(2→6) sialyltransferase followed by high resolution ¹H-NMR spectroscopic analysis of the isolated products enabled the assignment of the $\text{Galβ(1→4)GlcNAcβ(1→2)Man}\text{α(1→3)}\text{Man}$ branch as the most preferred substrate site for sialic acid attachment. The $\text{Galβ(1→4)GlcNAcβ(1→2)Man}\text{α(1→6)}\text{Man}$ branch appeared to be much less preferred and the Galβ(1→4)GlcNAcβ(1→4)Manα(1→3)Man sequence of triantennary structures was of intermediate preference for the sialyltransferase. The specificity of the β-galactoside α(2→6) sialyltransferase is thus shown to extend to structural features beyond the terminal $\text{N}$-acetyllactosamine units on the oligosaccharide chains of serum glycoproteins.     

The common structure in fucosyllactosaminolipids accumulating in human adenocarcinomas,and its possible absence in normal tissue

Two major glycolipids accumulating in a human primary liver adenocarcinoma, but absent in normal liver, were characterized as lacto-N-fucopentaosyl(III)ceramide and difucosyllacto-N-$\text{nor}$-hexaosylceramide, (Galβ1→4[Fucα1→3]GlcNAcβ1→3Galβ1→4[Fucα1→3]GlcNAcβ1→3Galβ1→4Glcβ1→1Cer), a new type of glycolipid with Le^x-determinant. Comparison of glycolipids bearing Le^x-determinant in various cases of human colonic adenocarcinoma, in adjacent normal mucosa tissue, and in erythrocytes reveals a possibility that glycolipids accumulating in human adenocarcinoma, but not in normal tissue, have a common structural unit as identified below:

     

Structure and Taste of Some Analogs of Naringin

The structures of acidic oligosaccharides synthesized by a transglycosylation reaction by Bacillus circulans β-galactosidase, using lactose as the galactosyl donor, and N-acetylneuraminic acid (NeuAc) and glucuronic acid (GlcUA) as the acceptors were investigated. Acidic oligosaccharides thus synthesized were purified by anion exchange chromatography and charcoal chromatography. The MS and NMR studies indicated that the acidic oligosaccharides from NeuAc were Galβ-(1→8)-NeuAc, Galβ-(1→9)-NeuAc, and Galβ-(1→3)-Galβ-(1→8)-NeuAc, and those from GlcUA were Galβ-(1→3)-GlcUA and Galβ-(1→4)-Galβ-(1→3)-GlcUA. These are novel acidic galactooligosaccharides.     

The asparagine-linked sugar chains of the glycoproteins in rat erythrocyte plasma membrane—Structural studies of the acidic oligosaccharides

Among the four acidic oligosaccharide fractions obtained by paper electrophoresis of the hydrazinolysate of the plasma membrane glycoproteins of rat erythrocytes, one was further separated into two by prolonged paper electrophoresis using 120-cm paper. Three fractions were mixtures of monosialyl oligosaccharides and two of disialyl oligosaccharides. After desialylation, their neutral portions were fractionated by Bio-Gel P-4 column chromatography and by affinity chromatography using a Con A-Sepharose column. Structural studies of the neutral oligosaccharides, thus obtained, indicated that at least 26 different complex-type oligosaccharides are present as a neutral portion of the acid oligosaccharides. Structurally they can be classified into bi-, tri-, and tetraantennary oligosaccharides with Manα1 → 6(Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4(±Fucα1 → 6)GlcNAc_OT as their common cores. Galβ1 → 3Galβ1 → 4GlcNAc, Siaα2 → 3Galβ1 → 4GlcNAc, Siaα2 → 6Galβ1 → 4GlcNAc, and a series of Siaα2 → (Galβ1 → 4GlcNAcβ1 → 3)_n · Galβ1 → 4GlcNAc were found as their outer chains. Their structures together with the structures of neutral oligosaccharides reported in the preceding paper indicated that the outer chain moieties of the asparagine-linked sugar chains of rat erythrocyte membrane glycoproteins are formed not by random concerted action of glycosyl transferases in Golgi membrane but by the mechanism in which the formation of one outer chain will regulate the elongation of others.     

Partial characterization of the acidic oligosaccharides from rat sublingual glycoprotein

Five sialic acid-containing oligosaccharides composed of nine, ten, twelve, thirteen and fifteen sugar residues, respectively, have been isolated from rat sublingual glycoprotein. Each oligosaccharide contained sialic acid, N-acetylglucosamine, N-acetylgalactosaminitol and galactose. The partial structures of desialyzed oligosaccharides, as determined by sequential degradation with specific glycosidases, are proposed to be: GlcNAc→^βGal→^βGlcNAc→^βGal→^βGlcNAc→^βGal→^βGlaNAc→^βGal→^βGlcNAc→^βGalNac-ol (oligosaccharide I), GlcNAc→^βGal→^βGlcNAc→^βGal→^βGlcNAc→^βGal→^βGlcNAc→^βGalNAc-ol (oligosaccharides II and III) and GlcNAc→^βGal→^βGlcNAc→^βGal→^βGlcNAc→^βGalNAc-ol (oligosaccharides IV and V).     

Effects of Divalent Cations on the Glycolipids from Cultured Mouse Neuroblastoma Cells

Abstract: The influence of divalent cations on glycosphingolipid metabolism was examined in the NB41A mouse neuroblastoma clonal cell line. HPLC methods were utilized to quantitate the effects on neutral glycolipids and monosialogangliosides. NB41A cells were shown to contain G_M3, G_M2, G_M1, G_D3, and G_D1a by HPLC and TLC. The neutral glycosphingolipids consisted of glucosylceramide (GlcCer), lactosylceramide (LacCer), GaINAc(β1→4) Gal(β1→4)Glc(β1→1)Cer (GgOse₃Cer), and GaINAc(β1→3)Gal(α1→4) Gal-(β1→4)Glc(β1→1)Cer (GbOse₃Cer) according to their HPLC behavior. Cells grown in the presence of 1.85 mm -EGTA showed a two- to threefold increase in G_M3 whereas other glycosphingolipids were only slightly affected. When cells were grown in the presence of 1.45 mm -EGTA plus 0.4 mm -EDTA a similar increase in G_M3 was observed but this change was now accompanied by decreases in G_M2, G_M1 GgOse₃Cer, and GbOse₄Cer. The EGTA-EDTA effects were reversed when growth was in the presence of Ca²⁺ sufficient to bind all chelator. Mn²⁺ replacement reversed the chelator effects differentially; G_M2 and G_M1 levels were the most sensitive to increases in Mn²⁺ concentration; GgOse₃Cer and GbOse₄Cer were also sensitive, whereas G_M3 was the least affected. These results suggest calcium serves an important regulatory role on G_M3 levels and that manganese concentration may regulate the levels of galactosamine-containing glycolipids in mouse NB41A neuroblastoma cells.     

Binding of simple carbohydrates and some N-acetyllactosamine-containing oligosaccharides to Erythrina cristagalli agglutinin as followed with a fluorescent indicator ligand

Erythrina cristagalli agglutinin, a dimeric lectin [J. L. Iglesias, et al. (1982) Eur. J. Biochem.123, 247–252] was shown by equilibrium dialysis to be bivalent for 4-methylumbelliferyl-β-d-galactoside. Upon binding to the lectin, this ligand showed a difference absorption spectrum with two maxima (at 322 and 336 nm) of equal intensity (Δ? = 1.2 × 10³m^?1 cm^?1). A similar spectrum with a comparable value of Δ? was obtained with 4-methylumbelliferyl-N-acetyl-β-d-galactosaminide. Binding of methyl-α-d-galactoside, lactose, and N-acetyllactosamine all produced small but equally intense protein difference spectra with a maximum (Δ? = 2.8 × 10² M^?1 cm^?1) at 291.6 nm. Upon binding of N-dansyl-d-galactosamine to the lectin, there was a fivefold increase in fluorescence intensity of this ligand. The association constant for N-dansyl-d-galactosamine was caused by a very favorable ΔS° of the dansyl group without affecting the strictly carbohydrate-specific character of binding. N-Dansyl-d-galactosamine was employed as a fluorescent indicator ligand in substitution titrations. This involved the use of simple carbohydrates, N-acetyllactosamine, and oligosaccharides which occur in the carbohydrate units of N-glycoproteins; the latter were Gal(β → 4)GlcNAc(β1 → 2)Man, Gal(β1 → 4)GlcNAc(β1 → 6)Man, and Gal(β1 → 4)GlcNAc(β1 → 6)[Gal(β1 → 4)GlcNAc(β1 → 2)]Man. The titrations were performed at two temperatures to determine the thermodynamic parameters. In the series N-acetyl-d-galactosamine, methyl-α-d-galactoside, and lactose, ?ΔH° increased from 24 to 41 kJ mol^?1; it increased further for N-acetyllactosamine and then remained unchanged for the N-acetyllactosamine-containing oligosaccharides (55 ± 1 kJ mol^?1). This indicated that the site specifically accommodated the disaccharide structure with an important contribution of the 2-acetamido group in the penultimate sugar. Beyond this, no additional contacts seemed to be formed. This conclusion also followed from considerations of ΔS° values which became more unfavorable in the above series (?23 to ?101 ± 4 J mol^?1 K^?1); the most negative value of ΔS° was observed with N-acetyllactosamine and the three N-acetyllactosamine-containing oligosaccharides.     

Preparation and characterization of antibody to galactosyl(α1 → 4)galactosyl(β1 → 4)glucosylceramide

Antiserum against galactosyl(α1 → 4)galactosyl(β1 → 4)glucosylceramide (globotriaosylceramide, Gb₃) was raised in rabbits by the administration of four weekly intramuscular injections of 1.5 mg of the purified glycolipid along with bovine serum albumin and Freund's complete adjuvant. AntiGb₃ activity was quantitated initially by immunoprecipitation employing Gb₃ mixed with 100-fold excess of lecithin and cholesterol (1 : 1 or 1 : 2, by wt.) as antigen. Subsequently, complement fixation tests done with antigen preparations containing Gb₃/lecithin/cholesterol (1 : 6 : 20, by wt.) showed antiGb₃ titres of up to 1 : 8192. Fractionation of the antiserum by BioGel A5m chromatography indicated the antibody was an IgM immunoglobulin. The partially purified antibody stimulated complement-dependent release of glucose from glucose-containing liposomes prepared with sphingomyelin/cholesterol/dicetylphosphate/Gb₃ (molar ratio, 100 : 75 : 11 : 1). The antibody crossreacted with the trisaccharide, Gal(α1 → 4)Gal(β1 → 4)Glc, but not with galactosylceramide, lactosylceramide, GM1 ganglioside, globotetraosylceramide, digalactosyldiglyceride or a number of low molecular weight saccharides.     

Structural characterization of glycolipids of rat small intestine having one to eight hexoses in a linear sequence

Eight different fractions containing glycolipids with 1 to 8 hexoses in a linear sequence were isolated from rat small intestine. The structure of the major components was established by mass spectrometry and proton nuclear magnetic resonance spectroscopy of the permethylated and permethylated-reduced (LiAlH₄) derivatives and by gas-liquid chromatography of degradation products of the native and permethylated or permethylated-reduced glycolipids. The major compounds were glucosylceramide, lactosylceramide, globotriaosylceramide, and a novel tetrahexosylceramide with the structure Gal α 1 → 3Galα1 → 4Galβ1 → 4Glcβ1 → 1Cer. In addition four minor compounds having five to eight hexoses were identified with the probable structures Galα1 → 3Galα1 → 3Galα1 → 4Galβ1 → 4Glcβ1 → 1Cer, Galα1 → 3Galα1 → 3Galα1 → 3Galα1 → 4Galβ1 → 4Glcβ1 → 1Cer, Gal1 → 3Gal1 → 3Gal1 → 3Gal1 → 3Gal1 → 4Gal1 → 4Glc1 → 1Cer, and Gal1 → 3Gal1 → 3Gal1 → 3Gal1 → 3Gal1 → 3Gal1 → 4Gal1 → 4Glc1 → 1Cer. In the pentahexosylceramide fraction a novel fucolipid was also present having the probable structure Fucα1 → 2Galα1 → 3Galα1 → 4Galβ1 → 4Galβ1 → 1Cer. The lipophilic part of the glycolipids was composed of trihydroxy 18:0 and dihydroxy 18:1 long-chain bases in combination with nonhydroxy and hydroxy 16:0–24:0 fatty acids. Glycolipid studies of isolated mucosal epithelial cells and the nonepithelial intestinal residue revealed a specific cell distribution of these hexosyl compounds. The two major components, glucosylceramide and globotriaosylceramide, were mainly located in the epithelial cells together with small amounts of lactosylceramide and tetrahexosylceramide. The epithelial cells practically lacked however the penta- to octahexosylceramides. The nonepithelial residue contained all hexosyl compounds. The fucolipid was exclusively present in the epithelial cells.     

Discoidin I from Dictyostelium discoideum and Interactions with Oligosaccharides: Specificity, Affinity, Crystal Structures, and Comparison with Discoidin II

Discoidin I (DiscI) and discoidin II (DiscII) are N-acetylgalactosamine (GalNAc)-binding proteins from Dictyostelium discoideum. They consist of two domains: an N-terminal discoidin domain and a C-terminal H-type lectin domain. They were cloned and expressed in high yield in recombinant form in Escherichia coli. Although both lectins bind galactose (Gal) and GalNAc, glycan array experiments performed on the recombinant proteins displayed strong differences in their specificity for oligosaccharides. DiscI and DiscII bind preferentially to Gal/GalNAcβ1-3Gal/GalNAc-containing and Gal/GalNAcβ1-4GlcNAcβ1-6Gal/GalNAc-containing glycans, respectively. The affinity of the interaction of DiscI with monosaccharides and disaccharides was evaluated using isothermal titration calorimetry experiments. The three-dimensional structures of native DiscI and its complexes with GalNAc, GalNAcβ1-3Gal, and Galβ1-3GalNAc were solved by X-ray crystallography. DiscI forms trimers with involvement of calcium at the monomer interface. The N-terminal discoidin domain presents a structural similarity to F-type lectins such as the eel agglutinin, where an amphiphilic binding pocket suggests possible carbohydrate-binding activity. In the C-terminal H-type lectin domain, the GalNAc residue establishes specific hydrogen bonds that explain the observed affinity (K_d = 3 × 10^− 4 M). The different specificities of DiscI and DiscII for oligosaccharides were rationalized from the different structures obtained by either X-ray crystallography or molecular modeling.     

Identification of the Molecular and Genetic Basis of PX2, a Glycosphingolipid Blood Group Antigen Lacking on Globoside-deficient Erythrocytes

The x₂ glycosphingolipid is expressed on erythrocytes from individuals of all common blood group phenotypes and elevated on cells of the rare P/P1/P^k-negative p blood group phenotype. Globoside or P antigen is synthesized by UDP-N-acetylgalactosamine:globotriaosyl-ceramide 3-β-N-acetylgalactosaminyltransferase encoded by B3GALNT1. It is the most abundant non-acid glycosphingolipid on erythrocytes and displays the same terminal disaccharide, GalNAcβ3Gal, as x₂. We encountered a patient with mutations in B3GALNT1 causing the rare P-deficient P₁^k phenotype and whose pretransfusion plasma was unexpectedly incompatible with p erythrocytes. The same phenomenon was also noted in seven other unrelated P-deficient individuals. Thin-layer chromatography, mass spectrometry, and flow cytometry were used to show that the naturally occurring antibodies made by p individuals recognize x₂ and sialylated forms of x₂, whereas x₂ is lacking on P-deficient erythrocytes. Overexpression of B3GALNT1 resulted in synthesis of both P and x₂. Knockdown experiments with siRNA against B3GALNT1 diminished x₂ levels. We conclude that x₂ fulfills blood group criteria and is synthesized by UDP-N-acetylgalactosamine: globotriaosylceramide 3-β-N-acetylgalactosaminyltransferase. Based on this linkage, we proposed that x₂ joins P in the GLOB blood group system (ISBT 028) and is renamed PX2 (GLOB2). Thus, in the absence of a functional P synthase, neither P nor PX2 are formed. As a consequence, naturally occurring anti-P and anti-PX2 can be made. Until the clinical significance of anti-PX2 is known, we also recommend that rare P₁^k or P₂^k erythrocyte units are preferentially selected for transfusion to P^k patients because p erythrocytes may pose a risk for hemolytic transfusion reactions due to their elevated PX2 levels.     

OLIGOSACCHARIDE STORAGE IN BRAINS FROM PATIENTS WITH FUCOSIDOSIS,GM1-GANGLIOSIDOSIS AND GM2-GANGLIOSIDOSIS (SANDHOFF'S DISEASE)1

Abstract— Analysis of whole autopsy brain from a patient with fucosidosis (α-fucosidase deficiency) revealed minor storage of H-antigen glycolipid [Fuc (α, 1→2) Gal-GlcNAc-Gal-Glc-Ceramide] and a slightly abnormal ganglioside composition in the form of a two-fold elevation of G_M1 and the presence of a fucose-containing glycolipid (a minor component) which co-migrated with G_D1a. The major storage materials in fucosidosis brain were an oligosaccharide (Fuc-Gal-GlcNAc-Man[Fuc-Gal-GlcNAc-Man]-ManGlcNAc) and a disaccharide [Fuc(α, 1→6)-GlcNAc] in the approximate ratio of 5:1. Lesser amounts of a related oligosaccharide (Gal-GlcNAc-Man[Gal-GlcNAc-Man]-Man-GlcNAc) were isolated from the brain of patients with G_M1-gangliosidosis (Types I and II) where the major storage material is known to be G_M1-ganglioside (Gal (β, 1→3)GalNAc(β, 1→4) [NeuNAcf(α, 2→3) Gal(β, 1→4)Glc-Ceramide). Similarly, a related oligosaccharide (GlcNAc-Man [GlcNAc-Man]-Man-GlcNAc) was isolated from the brain of a patient with a total deficiency of N-acetyl-β-d -hexosaminidase (Sandhoff variant of G_M2-gangliosidosis) where the major storage products are known to be G_M2-ganglioside (GalNAc (β 1→4) [NeuNAc (α, 2→3)Gal(β, 1→4)Glc-Ceramine) and its asialo derivative. These studies indicate that glycoproteins containing at least 2 mol of l -fucose per oligosaccharide unit are normally catabolized in human brain. Further, it appears that such glycoproteins are initially catabolized by an endo-N-acetylglucosaminidase to release an oligosaccharide which is then degraded by the sequential action of exo-glycosidases.     

ON THE STRUCTURE OF A NEW, FUCOSE CONTAINING GANGLIOSIDE FROM PIG CEREBELLUM

A new ganglioside, provisionally named GLIVa, was isolated in pure form from pig cerebellum. Ganglioside GLIVa is a disialoganglioside containing fucose. Its basic neutral glycosphingolipid core is the gangliotetraose ceramide: Gal, β 1 → 3 GalNAc, β 1 → 4 Gal, β 1 → 4 Glc, β 1 → Cer. Fucose is α-glycosidically linked to the 2-position of external galactose and one N-acetylneuraminic acid is linked to the other one by an α, 2 → 8 linkage. Thus the total structure of ganglioside GLIVa is the following: Fuc, α 1 → 2 Gal, β 1 → 3 GalNAc, β 1 → 4 (NeuAc, α 2 48 NeuAc, α 2 → 3) Gal, β 1 → 4 Glc, β 1 → Ceramide. According to the IUPAC-IUB Commission on Biochemical Nomenclature is indicated as II³α(NeuAc)₂ IV²αFuc-GgOse₄Cer.