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F Y Zeng

Publications and source records attributed to F Y Zeng.

10 recordsLinked to original sources
PubMed1992

Purification and properties of a fucoidan-binding protein from human placenta and its identification as immunoglobulin G.

1. A fucoidan-binding protein from human placenta was purified by affinity chromatography on immobilized fucoidan. 2. Characterization of molecular and immunological properties and peptide mapping indicated that the fucoidan-binding protein is an immunoglobulin G. 3. Cleavage with papain and transblot analysis with labelled fucoidan ascertained binding properties of the F(ab) fragments. 4. The specificity for fucoidan was furthermore substantiated by hapten inhibition of haemagglutination as well as by solid-phase assays with biotinylated fucoidan as ligand. The results emphasized the importance of structural features instead of simple ionic interactions. 5. Chemical modification with group-specific reagents to lysine, arginine, tryptophan, tyrosine and histidine resulted in substantial inactivation, their impact being markedly reduced by the presence of fucoidan in the cases of lysine, arginine and tryptophan.

Chromatography, Affinity↗
PubMed1992

Hb Q-Thailand [alpha 74(EF3)Asp-->His]: gene organization, molecular structure, and DNA diagnosis.

Hb Q-Thailand [alpha 74(EF3)Asp-->His] is often found in Thailand, China, and other Southeast Asian countries. The alpha-Q-Thailand gene is strongly linked to an alpha gene deletion and has important implications in the identification and diagnosis of hemoglobinopathies and thalassemias. The alpha-Q-Thailand mutation was previously mapped to the alpha 1 gene in a study of Chinese patients. In this paper, a Thai patient with Hb Q-Thailand/Hb H disease and his mother were studied at the DNA level, and the gene organization of Hb Q-Thailand in the Thai patient was found to be the same as that of Chinese patients (i.e. the Hb Q-Thailand gene is located on the alpha 1 gene of chromosome #16, while the -4.2 kb or leftward deletion involves the alpha 2 gene). Also, the GAC-->CAC mutation proposed at codon 74, has been confirmed by DNA sequencing and a simple and accurate method for diagnosis of the Hb Q-Thailand variant has been developed based on restriction enzyme analysis. Since the GAC-->CAC mutation generates new cutting sites for both restriction enzymes Apa LI and Hgi AI, polymerase chain reaction amplification of a specific region around codon 74, followed by digestion with these enzymes and agarose gel electrophoresis of the digested products, permits rapid and accurate identification of Hb Q-Thailand.

Base Sequence↗
PubMed1992

Study of the RNA splicing defect in the common Chinese beta-thalassemia gene, IVS-II nt. 654 C-->T by using mRNA/PCR.

With direct sequencing of the amplified cDNA, we analysed the transcript and mRNA splicing defect in a common Chinese beta-thalassemia mutant (IVS-II nt. 654 C-->T). The result shows that this mutant gene would not only produce abnormally processed beta-globin mRNA, but also transcribes a small amount of normally spliced mRNA, hence leading to beta+ thalassemia. The method described herein provides a simple and sensitive approach to the studies of gene expression and molecular defects in genetic diseases at transcriptional level.

Amino Acid Sequence↗
PubMed1992

Mammalian fetuin-binding proteins sarcolectin, aprotinin and calcyclin display differences in their apparent carbohydrate specificity.

The interferon antagonist sarcolectin, the protease inhibitor aprotinin and calcyclin whose expression is regulated by growth stimulation in quiescent fibroblasts display sialic acid-dependent binding to fetuin, visualized by solid-phase assays using biotinylated fetuin. The potential functional importance of this property prompted its comparative characterization with an array of neutral or negatively charged sugars, sulfated polysaccharides and sialoglycoproteins as inhibitors of binding of biotinylated fetuin to the immobilized proteins. The results revealed that this activity of sarcolectin and calcyclin is nearly unaffected by charge-free carbohydrates in contrast to aprotinin, calcyclin exhibits a notable affinity for Neu5Gc and together with aprotinin for phosphorylated sugars, and that sarcolectin's binding is affected to the highest extent by sulfated sugars relative to aprotinin and calcyclin.

Aprotinin↗
PubMed1991

Diagnosis of thalassemia using cDNA amplification of circulating erythroid cell mRNA with the polymerase chain reaction.

We have developed a technique to diagnose the alpha- and beta-thalassemia (thal) syndromes using the polymerase chain reaction to amplify cDNA copies of circulating erythroid cell messenger RNA (mRNA) so as to quantitate the relative amounts of alpha-, beta-, and gamma-globin mRNA contained therein. Quantitation, performed by scintillation counting of 32P-dCTP incorporated into specific globin cDNA bands, showed ratios of alpha/beta-globin mRNA greater than 10-fold and greater than fivefold increased in patients with beta 0- and beta (+)-thal, respectively, as well as a relative increase in gamma-globin mRNA levels. Conversely, patients with alpha-thalassemia showed a decreased ratio of alpha/beta-globin mRNA proportional to the number of alpha-globin genes deleted. This methodology of ascertaining ratios of globin mRNA species provides a new, simplified approach toward the diagnosis of thalassemia syndromes, and may be of value in other studies of globin gene expression at the transcription level.

Base Sequence↗
PubMed1991

Carbohydrate-binding specificity of calcyclin and its expression in human tissues and leukemic cells.

Binding of biotinylated fetuin in a solid-phase assay served as activity assay for purification of calcyclin, the product of a cell growth-related cDNA with homologies to Ca(2+)-binding proteins. Asialofetuin failed to bind to calcyclin, emphasizing the importance of sialic acids. Binding of fetuin was most effectively reduced by N-glycolylneuraminic acid within a panel of mostly negatively charged sugars. Bovine submaxillary mucin and the ganglioside GM1, but not asialo-GM1, proved more effective than neoglycoproteins, carrying negatively charged carbohydrate moieties. Extension of N-acetyl-neuraminic acid to its lactosyl derivative increased its inhibitory potency. Among charge-free carbohydrate residues, only N-acetylglucosamine, lactose, and mannose, but not fucose, melibiose, or N-acetylgalactosamine affected fetuin binding, substantiating the inherent selectivity. Chemical modification with group-specific reagents revealed that lysine and arginine residues appear to be involved in ligand binding that is optimal in the presence of Ca2+, but not Zn2+ and stable up to 1 m NaCl. Biotinylation of calcyclin by modification of carboxyl groups facilitated performance of solid-phase assays with calcyclin in solution, yielding similar results with (neo)glycoproteins in relation to assays with immobilized calcyclin, thereby excluding an impact of binding to nitrocellulose on calcyclin's specificity. Subcellular fractionation disclosed the presence of fetuin-binding activity in all fractions, the specific activity decreasing from the nuclear to the particulate cytoplasmic fraction and the cytoplasmic supernatant. Affinity-purified antibodies were employed to detect high levels of calcyclin expression in acute lymphoblastic, myelogenous, and monocytic leukemia cell lines, but not in myeloma or lymphoblastoid cells. In comparison, most cells were nearly devoid of an O-acetylsialic acid-specific protein that is more abundant in various tissue types than calcyclin.

Acetylglucosamine↗
PubMedDate not supplied

Sialic acid-binding proteins: characterization, biological function and application.

The last decade has witnessed steadily growing support for the notion that the carbohydrate portion of glycoconjugates is not merely an inert structural addition to the protein or lipid backbone. Considerable attention has been given to the chemical composition of glycosidic residues in such heteropolymers. Sialic acids are frequently occurring components of oligosaccharide side chains in glycoconjugates of most higher animals and a few microorganisms. They appear to play an important role as ligands in glycobiological interactions. Mediation of a proposed protein-carbohydrate recognition will necessarily involve a binding protein with the respective specificity. Such proteins thus are able to serve as receptors for certain types of carbohydrate moieties like sialic acids in vivo. Various members of this class of proteins have already proven their value as analytical tools in studying expression and localization of defined sialoglycoconjugates. These proteins attract much attention due to both their functions in situ and their potential as laboratory tools in glycoconjugate research in areas like biochemistry or histology. We present a survey of the purification, characterization and application of this class of proteins to illustrate the status of knowledge and the current directions of research in this field.

Animals↗