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K T Lin

Publications and source records attributed to K T Lin.

65 records · Page 4Linked to original sources
PubMed1976

Studies on camel hemoglobin. 1. Physico-chemical properties and some structural aspects of camel hemoglobin (Camelus dromedarius).

Hemoglobin from an adult camel (Camelus dromedarius) was prepared from the red cell lysate by CM- and DEAE-cellulose chromatography. The purified hemoglobin showed a lesser mobility on starch gel electrophoresis at pH 8.5 than that of human hemoglobin C. Native camel hemoglobin contains 95-99% alkali-resistant hemoglobin and in soluble in 2.94 M K2HPO4/KH2PO4 buffer. Different forms of camel hemoglobin show similar ammonium sulfate precipitation curves. Indirect evidence for the stability of camel hemoglobin solutions was obtained from several sources. Spontaneous met-hemoglobin formation is extremely slow and minimal quantities of degradation products appear on starch gel electrophoresis and on chromatographic separation. The alpha and beta chains of camel hemoglobin A were separated on a CM-23 column by the use of a pyridine formate gradient. Large peptide fragments were obtained by tryptic digestion of maleylated alpha and beta chains. The N-terminal structure of the alpha and beta chains and of tryptic maleylated peptides derived from alpha and beta chains are presented. Between adult camel hemoglobin and adult human hemoglobin six amino acid differences in the N-terminal 20 amino acid residues of the alpha chain, at residues: 4, 5, 12, 14, 17, and 19; eight amino acid substitutions were found in the beta chain at positions: 4, 5, 6, 9, 12, 13, 16, and 19. Substitutions at alpha5 Ala leads to Lys, and beta19 Asn leads to Lys, increase the net positive charge of camel hemoglobin by two, while other substitutions result in no charge differences. The molecular basis of the stability of camel adult hemoglobin is discussed.

Amino Acid Sequence↗
PubMed1976

Purification of p-hydroxyphenylpyruvate hydroxylase from rat liver--requirement for cofactors.

The enzyme p-hydroxyphenylpyruvate hydroxylase (EC 1.13.11.27) from rat liver was studied with the assay method which measures the release of 14CO2 from p-hydroxyphenyl [carboxy-14C]pyruvate. Extensive dialysis of the crude enzyme extract against Tris buffer or purification involving ammonium sulfate, gel filtration, and ion exchange results in loss of enzyme activity that can be reactivated by Fe2+, dichlorophenolindophenol, and various other agents. The effect of these activators depends critically on their final concentration in the assay media. A 70-fold purification of the enzyme fraction yielded a preparation which behaved as a single protein band in Sephadex G-150. It had an isoelectric point at 5.85 and molecular weight of 63 000. The enzyme obtained appears to be different in some respects from those described by other workers from the liver of dog, human, chicken, and frog.

2,6-Dichloroindophenol↗
PubMedDate not supplied

Chemical structure of and immune response to polysaccharides of Streptococcus pneumoniae.

By use of rabbit antisera, extensive cross-reactions were demonstrated among pneumococcal (Danish) types 6A and 6B, types 9N, 9A, 9L, and 9V, and types 19F and 19A. The structural similarity of the group 6 polysaccharides was associated with extensive immunogenicity in humans. In contrast, immunization of humans with type 19F or 19A may not induce sufficient cross-protection. The type 19F polysaccharide has the structure of a linear polymer of N-acetylmannosamine-glucose-rhamnose phosphate. Danish type 19A (type 57 in the United States system) polysaccharide contains this repeating unit and, in addition, has side chains of N-acetylglucosamine-galactose phosphate and fucose phosphate. Maternal immunization with type 19F or type 6A polysaccharide during pregnancy elicited high antibody formation in the offspring. Young mice, which received an additional dose of polysaccharide at two weeks of age, showed a higher antibody response than did those that did not receive polysaccharide. These studies reveal that the extensive cross-immunogenicity of pneumococcal group polysaccharides has a basis in chemical structure. Maternal immunization with pneumococcal polysaccharides may enhance the immune response of neonates.

Animals↗
PubMedDate not supplied

Studies on vaccine control and immunogenicity of polysaccharides of Streptococcus pneumoniae.

An immunoelectrophoretic method was devised for quantitation of 14 polysaccharide components in the pneumococcal vaccine, and for determination of their stability in the final container. By this method the individual polysaccharide types, 1, 2, 3, 4, 6A, 8, 9N, 12F, 18C, 19F, 23F, and 25 (Danish nomenclature), were found to be present at 80%-123% of the manufacturer's listed concentrations. Pneumococcal polysaccharide types 3, 6A, 9N, and 19F, used as representative types, were heated at 37C for 24 hr and stored at 4 C. The concentrations of these polysaccharides remained constant over a 12-month period, and the molecular sizes of types 3 and 9N were stable during storage. In contrast, the molecular sizes of types 6A and 19F declined gradually during the 12-month storage period. Pneumococcal type 19F polysaccharide was conjugated to various proteins, i.e., bovine serum albumin, human immunoglobulin, and pneumococcal R61 cell wall protein, by the method of reductive amination. Immunization of mice with 19F polysaccharide-protein conjugates resulted in formation of more antibody than was found in the control group. Young mice exposed to pneumococcal type 19F polysaccharide-protein conjugate during gestation and suckling exhibited a greater antibody response than did mice that received no type 19F polysaccharide-protein conjugate while suckling or received the conjugate only when they were only two weeks of old.

Animals↗
PubMedDate not supplied

14(R),15(S)-epoxyeicosatrienoic acid (14(R),15(S)-EET) receptor in guinea pig mononuclear cell membranes.

A high affinity binding site for 14(R),15(S)-EET, one of the major cytochrome P-450 metabolites of arachidonic acid (AA) in blood vessels, liver, kidney and urine of patients with pregnancy-induced hypertension, has been identified in a membrane preparation from guinea pig mononuclear (GPM) cells. Using a radioligand assay, binding of 14(R),15(S)-[3H]EET to its receptor site was saturable, specific and reversible. Scatchard analysis of saturation binding studies yielded a dissociation constant (Kd) of 5.7 x 10(-9) M, and maximum number of binding sites (Bmax) of 2.4 pmol/mg membrane protein. The specificity of the binding site was determined by competition studies. 14(S),15(R)-EET and 8,9-EET had a Ki of 6.3 and 8.8 nM, respectively, followed by 12(R)-HETE and LTD4. 12(S)-HETE and 5,6-EET were even less effective as a competitive inhibitor of radioligand and binding with Ki values from 2 to 20 microM. Receptor antagonists for TxA2, LTB4, LTD4 and PAF failed to displace 14(R),15(S)-[3H]EET from its binding site on GPM cell membranes. The results correlate well with the reported biological functions of 14,15-EET. In view of its potent biological activities, 14,15-EET may exert its cellular function through the binding and activation of its stereo-specific cell surface binding sites or receptor.

8,11,14-Eicosatrienoic Acid↗