PubMed · 4278781
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R B Stoughton. 1974. Local toxicity.. https://doi.org/10.1002/cpt1974165part2964
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We previously described a diverse family of sulfated anionic N-linked oligosaccharides released by peptide: N-glycosidase F (PNGaseF) from calf pulmonary artery endothelial (CPAE) cells (Roux, L., Holoyda, S., Sundblad, G., Freeze, H.H., and Varki, A. (1988) J. Biol. Chem. 263, 8879-8889). Since a major fraction of the intact lung consists of endothelial cells, we reasoned that bovine lung might be a rich source of similar molecules. Total N-linked oligosaccharides from bovine lung acetone powder were released by PNGaseF, labeled by [3H]NaBH4 reduction, and the anionic fractions were studied with a variety of techniques. The sugar chains with lesser negative charge (designated Class I) share several properties of conventional multiantennary complex-type chains. However, unlike the case with CPAE cells, sialic acids account only for a minority of the anionic properties and only a small proportion carry sulfate esters. A variety of different treatments indicate that most of the unexplained negative charge is due to multiple carboxylic acid groups. Resistance to beta-glucuronidase and alpha-iduronidase suggests that these may be previously undescribed modifications of mammalian oligosaccharides. The most highly charged N-linked chains (designated Class II) are more similar in general structure to the corresponding ones from CPAE cells, although relatively more abundant. Their high charge is primarily due to chondroitin sulfate, heparin/heparan sulfate, or keratan sulfate glycosaminoglycan chains. Sequential digestion studies suggest that a significant proportion of these molecules have more than one type of glycosaminoglycan chain associated with them. Compositional analysis indicates the presence of xylose residues in Class II, but not Class I molecules. However, unlike the case with conventional glycosaminoglycans, these residues are not at the reducing terminus. Most previously reported structures of complex-type N-linked oligosaccharides are derived from the glycoproteins of blood cells, plasma, or the secretions of cultured mammalian cells. This library of N-linked oligosaccharides from an intact mammalian organ (lung) contains a high proportion of novel anionic sugar chains whose structures are different from conventional complex-type sialylated chains and only partially related to those from CPAE cells. Further exploration of the N-linked chains of intact mammalian tissues seems warranted.
The effects of methanol, acetone, and ethylene glycol (up to 50% v/v) on elementary steps in the reactions of horseradish peroxidase (HRP) and lactoperoxidase (LPO) were studied by means of the stopped-flow method and the difference spectrum. The rate constant (k3,app) of the oxidation reaction of p-cresol with HRP compound II was remarkably reduced in the presence of organic solvents (to 2.3%, 1.8% and 9.4% of the original value in the presence of 50% (v/v) of methanol, acetone and ethylene glycol, respectively), then to a lesser degree were decreased the rate of the oxidation reaction with LPO compound II, and the rate of the oxidation reaction with HRP compound I. These reductions in the reaction rates were not due to competitive inhibition of the solvents, but considered to be related to the degree of exposure of the electron transfer route to the medium. While the rate constant of compound I formation (k1,app) was moderately affected by organic solvents in the case of HRP, the reaction rate with LPO was scarcely affected by organic solvents, being in harmony with the compact heme crevice which probably hampers penetration of solvent molecules. The rate constant (k2,i,app) of the oxidation reaction of an iodide ion by HRP compound I was also hardly affected by the solvents. On the basis of these facts, the mechanism of electron transfer from donors to compound I and compound II is discussed.
To summarize, CHF predisposes to postabsorptive ketosis in relation to the severity of venous congestion. A simple and fully noninvasive measurement of breath acetone may add to the diagnostic assessment of patients with CHF.