PubMed Health⌕ Search

Biomedical subjects

K K Yabusaki

Publications and source records attributed to K K Yabusaki.

8 recordsLinked to original sources
PubMed1983

A new rapid slide agglutination test for amniotic fluid phosphatidylglycerol: laboratory and clinical correlation.

A new rapid slide agglutination test (Amniostat-FLM/AFLM) for amniotic fluid phosphatidylglycerol has been developed. One hundred ninety-three samples of amniotic fluid were tested for lecithin/sphingomyelin (L/S) ratio and phosphatidylglycerol by thin-layer chromatography and fluorescence polarization and compared with the AFLM. All four tests agreed in 123/193 cases. Phosphatidylglycerol and AFLM were concordant in 176/193 cases. From these samples, data were available on 105 neonates, of whom 74 were delivered within 72 hours of amniocentesis. All positive AFLM tests were associated with absence of hyaline membrane disease, of 22 negative tests, eight babies had hyaline membrane disease. Thus, preliminarily, it appears that this is a useful, rapid test for assessing fetal lung maturity, which like other tests is reliable when indicating maturity but has a high incidence of falsely immature results.

Agglutination Tests↗
PubMed1979

Conformational changes associated with complex formation between a mycobacterial polymethylpolysaccharide and palmitic acid.

The anomeric proton magnetic resonances of Mycobacterium smegmatis 3-O-methylmannose polysaccharide have chemical shifts intermediate betwen those of nonaglucoamylose and alpha-cyclodextrin, and on addition of palmitic acid most of these resonances are shifted upfield toward that of the cyclodextrin. This suggests that the methylated polysaccharide could have a conformation with some secondary structure intermediate between those of the two reference compounds, and that it forms a tightened coil upon addition of the lipid which yields an inclusion complex with the polysaccharide. The change in chemical shift is linear with lipid concentration, which indicates that the complex undergoes rapid exchange with free polysaccharide. The changes in proton chemical shifts of the polysaccharide and of the palmitic acid are consistent with the fatty acid being inserted in the coiled polysaccharide with its carboxyl group near the methyl aglycon.

Chemical Phenomena↗
PubMed1978

S-trifluoroacetonyl-coenzyme A:a 19F analogue of acetyl-coenzyme A.

S-Trifluoroacetonyl-coenzyme A has been synthesized in 87% yield by reaction of 1,1,1-trifluoro-3-bromopropanone with trilithium coenzyme A in presence of pyridine. The compound was characterized by its ultraviolet absorption spectrum and 1H and 19F nuclear magnetic resonance spectra. The alpha-methylene protons of the S-trifluoroacetonyl group exchanged with D2O and showed a pKa of 9.85 in S-trifluoroacetonylmercaptoethanol. S-Trifluoroacetonyl-coenzyme A is a competitive inhibitor of porcine heart citrate synthetase (Ki = 0.16 mM). It forms a binary complex with the enzyme and a ternary complex with enzyme/oxaloaetate binary complex, as evidenced ty the 19F shift. S-Trifluoracetonyl-coenzyme A and S-trifluoroacetonylmercaptoethanol form weak to moderately strong complexes with alpha-cyclodextrin and show little or no interaction with the methylglucose polysaccharide and lipopolysaccharides from Mycobacterium smegmatis [Smith, W. L., & Ballou, C. E. (1973) J. Biol. Chem. 248, 7118]. S-Trifluoroacetonylmercaptoethanol probably forms an inclusion complex with alpha-cyclodextrin because the interaction is reversed by compounds that do form inclusion complexes.

Acetyl Coenzyme A↗
PubMed1978

Interaction of mycobacterial polymethylpolysaccharides with paranaric acid and palmitoyl-coenzyme A: structural specificity and monomeric dissociation constants.

The long-chain polyenoic fatty acids alpha- and beta-paranaric acid form complexes with the 6-O-methylglucose polysaccharide from Mycobacterium smegmatis as demonstrated by an enhanced fluorescence emission of the paranaric acid. This interaction is eliminated by digestion of the methylglucose polysaccharide with alpha-amylase and glucoamylase, which removes four hexose units from the nonreducing end of the chain. Titration of the methylglucose polysaccharide with either paranaric acid isomer suggests formation of a 1:1 complex with a dissociation constant (K(d)) of 0.4 muM. The fluorescence emission of this complex is quenched by palmitoyl-CoA, which indicates that the paranaric acid can be displaced by the acoyl-CoA, a conclusion confirmed by gel filtration. The presumed polysaccharide/palmitoyl-CoA complex has a K(d) of about 0.1 muM. Acoyl-CoA derivatives with shorter fatty acid chains and free palmitic acid complete less effectively, indicating that they form weaker complexes with the polysaccharide. The methylmannose polysaccharides with 12 or 13 sugar units also complex paranaric acid strongly (K(d) approximately 0.4 muM), whereas the isomer with 11 sugar units complexes weakly.The methylglucose polysaccharide has been coupled to L-tryptophan methyl ester. The fluorescence emission spectrum of the attached tryptophan group is shifted to a shorter wavelength relative to N-acetyl-L-tryptophan methyl ester, and this effect is enhanced in the corresponding derivative made with the amylase-digested polysaccharide. The circular dichroism spectrum of the polysaccharide-tryptophan derivative shows three bands with negative ellipticity, in the 270-300 nm region, not observed in the amylase-digested derivative. These results imply that the tryptophan is in a more structured environment in the former than in the latter derivative. alpha-Paranaric acid binds to the polysaccharide-tryptophan conjugate and shows an enhanced fluorescence emission with partial quenching of the tryptophan fluorescence emission, suggestive of Förster energy transfer from tryptophan to paranaric acid.

Acyl Coenzyme A↗
PubMed1976

1-Hydroxy-2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholine. A useful intermediate in the synthesis of short acyl chain 1-acyl-sn-glycero-3-phosphorylcholines.

The synthesis of 1-acyl-sn-glycero-3-phosphorylcholines in particular those containing short fatty acyl chains are described. The method involves the use of 1-acyl-2-tert-butyl-dimethylsilyl-sn-glycero-3-phosphorylcholines which can be readily prepared by reacting hens' egg yolk 1-acyl-sn-glycero-3-phosphorylcholines with tert-butyldimethylchlorosilane with imidazole as catalyst and dimethylformamide as solvent. Deacylation of the 1-acyl-2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholines with saturated anhydrous potassium carbonate in methanol yields the 2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholine. Reacylation of the 2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholine with fatty acyl anhydride in the presence of 4-dimethylaminopyridine in anhydrous chloroform followed by removal of the tert-butyldimethylsilyl protecting group by treatment with dry hydrogen chloride gas in anhydrous chloroform at 0 degrees yields the desired 1-acyl-sn-glycero-3-phosphorylcholine. Various facets of the reactions involved in developing the synthetic procedures in this study are discussed.

Glycerylphosphorylcholine↗
PubMed1975

Binding of calcium to phosphatidylcholines as determined by proton magnetic resonance and infrared spectroscopy.

The interactions of calcium, magnesium, and the rare earth cations, cerium, neodymium, and praseodymium, with phosphatidylcholines were studied by proton magnetic resonance and infared spectroscopy. The calcium-induced chemical shifts for the various protons of phosphatidylcholine were C alpha choline greater than C beta choline greater than N(CH3)3 greater than C3 glycerol. No significant chemical shifts were observed for the C1 and C2 glycerol protons. None of the acyl chain protons were affected by the presence of calcium. Analysis of the salt-induced chemical shifts yielded binding curves with an excellent fit with the theoretical. The vicinal coupling constants for the various protons of phosphatidylcholine did not appear to change in the presence of calcium. The lanthanide-induced isotropic shifts for the protons of phosphatidylcholines followed the order Cbeta choline greater than C3 glycerol greater than Calpha choline greater than N(CH3)3. Examination of the P=O stretching band (1150-1300 cm-1) of phosphatidylcholines by differential infrared spectroscopy showed that this band shifted to shorter wavelengths in the presence of calcium. The site of calcium binding to phosphatidylcholines as deduced from the proton magnetic resonance and infrared data is discussed in light of the high specificity for calcium in enhancing the amino-catalyzed methanolysis of phosphatidylcholines.

Binding Sites↗