Reference

Binding specificity of serum amyloid P component for the pyruvate acetal of galactose

Binding specificity of serum amyloid P component for the pyruvate acetal of galactose. Hind, C. R. K.; Collins, P. M.; Renn, D.; Cook, R. B.; Caspi, D.; Baltz, Marilyn L.; Pepys, M. B. (R. Postgrad. Med. Sch., Hammersmith Hosp., London W12 0HS, UK). J. Exp. Med., 159(4), 1058-69 (English) 1984. CODEN: JEMEAV. ISSN: 0022-1007. DOCUMENT TYPE: Journal CA Section: 6 (General Biochemistry) The amt. of serum amyloid P component (SAP) from human, mouse, and plaice (Pleuronectes platessa) serum able to bind to agarose from different sources reflect precisely the pyruvate content of the agaroses. Methylation with diazomethane of the carboxyl groups in the pyruvate moiety of agarose completely abolishes SAP binding to agarose. The pyruvate in agarose exists as the 4,6-pyruvate acetal of b-D-galactopyranose. This galactoside was synthesized using a novel procedure and its structure was detd. by anal. of its NMR spectra; it inhibits all known Ca-dependent binding reactions of SAP. The R isomer of the cyclic acetal, Me 4,6-O-(1-carboxyethylidene)-b-D-galactopyranoside (MObDG), was effective at millimolar concn. and was more potent than its noncyclic analog, whereas pyruvate, D-galactose, and Me b-D-galactopyranoside were without effect. 600-22-6 and 90267-94-0 which are cas registry numbers of substances are two of reagents here. The autologous protein ligands of SAP presumably, therefore, express a structural determinant(s) that stereochem. resemble MObDG. Availability of this specific, well-characterized, low mol. wt. ligand for SAP should facilitate further investigation of the function of SAP and its role in physiol. and pathophysiol. processes. .

Characterization of the specific pyruvate transport system in Escherichia coli K-12

Characterization of the specific pyruvate transport system in Escherichia coli K-12. Lang, Verna J.; Leystra-Lantz, Cheryl; Cook, Robert A. (Dep. Biochem., Univ. West. Ontario, London, ON N6A 5C1, Can.Chemicals with cas numbers 50-21-5 and 600-22-6 also play role.). J. Bacteriol., 169(1), 380-5 (English) 1987. CODEN: JOBAAY. ISSN: 0021-9193. DOCUMENT TYPE: Journal CA Section: 10 (Microbial Biochemistry) A mutant of Escherichia coli K-12 lacking pyruvate dehydrogenase and phosphoenolpyruvate synthase was used to study the transport of pyruvate by whole cells. Uptake of pyruvate was maximal in mid-log phase cells, with a Michaelis const. for transport of 20 mM. Pretreatment of the cells with respiratory chain poisons or uncouplers, except for arsenate, inhibited transport by ￡95%. Lactate and alanine were competitive inhibitors, but at nonphysiol. concns. The synthetic analogs, 3-bromopyruvate and pyruvic acid Me ester inhibited competitively. The uptake of pyruvate was also characterized in membrane vesicles from wild-type E. coli K-12. Transport required an artificial electron donor system, phenazine methosulfate and Na ascorbate. Pyruvate was concd. in vesicles 7- to 10-fold over the external concn., with a Michaelis const. of 15 mM. Energy poisons, except arsenate, inhibited the transport of pyruvate. Synthetic analogs such as 3-bromopyruvate were competitive inhibitors of transport. Lactate initially appeared to be a competitive inhibitor of pyruvate transport in vesicles, but this was a result of oxidn. of lactate to pyruvate. The results indicate that uptake of pyruvate in E. coli is via a specific active transport system. .