Pentose Metabolism Research Articles

End-stage renal disease and diabetes catalyze the formation of a pentose-derived crosslink from aging human collagen.

Structure elucidation of a specific fluorophore from the aging extracellular matrix revealed the presence of a protein crosslink formed through nonenzymatic glycosylation of lysine and arginine residues. The unexpected finding that a pentose instead of a hexose is involved in the crosslinking process suggested that the crosslink, named pentosidine, might provide insight into abnormalities of pentose metabolism in aging and disease. This hypothesis was investigated by quantitating pentosidine in hydrolysates of 103 human skin specimens obtained randomly at autopsy. Pentosidine level was found to increase exponentially from 5 to 75 pmol/mg collagen over lifespan (r = 0.86, P less than 0.001). A three- to tenfold increase was noted in insulin-dependent diabetic and nondiabetic subjects with severe end-stage renal disease requiring hemodialysis (P less than 0.001). Moderately elevated levels were also noted in some very old subjects, some subjects with non-insulin dependent diabetes, and two subjects with cystic fibrosis and diabetes. The cause of the abnormal pentose metabolism in these conditions is unknown but may relate to hemolysis, impaired pentose excretion, cellular stress, and accelerated breakdown of ribonucleotides. Thus, pentosidine emerges as a useful tool for assessment of previously unrecognized disorders of pentose metabolism in aging and disease. Its presence in red blood cells and plasma proteins suggests that it might be used as a measure of integrated pentosemia in analogy to glycohemoglobin for the assessment of cumulative glycemia.

Fermentation Products from Carbohydrate Metabolism in Pediococcus pentosaceus PC39

Pediococcus pentosaceus PC39 was grown in batch culture on selected hexoses and pentoses. The spent culture medium was analyzed by high performance liquid chromatography. Neither hexose metabolism nor pentose metabolism resulted in end-product patterns normally predicted for this organism based on its traditional classification. In general, the total amount of by-products, particularly ethanol, was unexpectedly high.

Xylose fermentation

The fermentation of xylose and xylulose with yeasts, bacteria and fungi as well as the combination of yeasts and bacterial xylose isomerase, has been reviewed. Methods to measure oxygenation in fermentation with yeasts are compared and the relationship between pentose metabolism in yeasts and oxygenation during fermentation is discussed. The influence of substrate concentration, substrate specificity, pH, temperature, inhibitors and other additives in yeast fermentation have been summarized. Batch fermentation has been compared to continuous fermentation, fermentation with cell recirculation and immobilization. The fermentation of lignocellulose and lignocellulose hydrolysates with bacteria, yeasts and fungi has also been reviewed. Throughout this review, product concentration, product yield and productivity have been compared with values generally achieved in batch fermentation of hexoses: 50 g l −1, 0.5, and 2 g l −1 h −1.

Metabolism of hexoses and pentoses by Cellulomonas uda under aerobic conditions and during fermentation

Cellulomonas uda utilized the constituent carbohydrates of cellulose and hemicellulose under aerobic conditions and during fermentation. Balances of fermentation of cellobiose, glucose, xylose, L-arabinose, mannose, galactose, fructose, and sucrose were determined. Products formed were ethanol, L-lactic acid, acetic acid, formic acid, and succinic acid. In contrast to acetic acid, a small amount of succinic acid was utilized under aerobic conditions but only together with glucose. Ethanol was not consumed either under aerobic conditions or during fermentation. The rate of both glucose uptake and lactic acid excretion during fermentation increased with increasing initial pH values of 7 to 9. The intracellular concentration of ethanol at the end of glucose fermentation was 20 times higher than that in the culture supernatant. Switching from aerobic to fermentation conditions increased specific activities of fructose-6-phosphate kinase and fructose-1,6-bisphosphate aldolase, both key enzymes of the fructose-1,6-bisphosphate pathway, whereas those of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, key enzymes of the pentose phosphate cycle, were not affected significantly. Of the enzymes involved in pyruvic acid metabolism, pyruvate formate lyase, L-lactate dehydrogenase, and alcohol dehydrogenase were demonstrated in cell-free extracts. Fructose-1,6-bisphosphate had an activating effect on L-lactate dehydrogenase. Alcohol dehydrogenase was inhibited competitively by high concentrations of ethanol and noncompetitively by NAD.

Bioconversion of hemicellulosics.

Hemicellulose carbohydrates comprise a significant proportion of available biomass resources such as agricultural residues and wood wastes. These sugars, of which D-xylose is the most abundant, can be converted to valuable fuels and chemical feedstocks by bacteria, yeasts and mycelial fungi. Examination of the metabolism of pentoses by these microorganisms, reveals major differences in both the initial reactions of sugar breakdown and the nature of the resultant endproducts. Wide variability exists in the ability of microbes to utilize D-xylose and its ketose isomer, D-xylulose. Methods for recovery of hemicellulose sugars include autohydrolysis, alkaline or dilute acid extraction and enzymatic hydrolysis. Processes indicating the feasibility of ethanol manufacture from corn stover, wheat straw and wood have been studied.

Untersuchungen zum Pentose- und Pentitolstoffwechsel bei Staphylococcus xylosus und Staphylococcus saprophyticus

The degradation of pentoses and xylitol, respectively is a meaningful taxonomic parameter for the distinction of the coagulase-negative staphylococci Staphylococcus xylosus and S. saprophyticus . It is, therefore, of interest to learn more about the catabolism of these C 5 -sugars and sugar alcohols. The following pathway for the breakdown of pentoses and xylitol has been found in S. xylosus and S. saprophyticus : inducible uptake of unsubstituted carbohydrates; phosphoenolpyruvate phosphotransferase system (PTS) is not involved in the uptake of pentoses and xylitol. Isomerization of pentoses and dehydration of xylitol is inducible. Phosphorylation probably occurs on ketopentoses, since activity for D-ribulokinase could be detected in D-ribose grown cells, but neither activity for pentokinases nor D-ribose-5-phosphate-isomerase could be demonstrated. Therefore, the pathway is analogous to the metabolism of pentoses and pentitol in Enterobacteriaceae , exceptionally for D-ribose, and differs from the degradation of pentitols by Lactobacillaceae . Growth with D-xylose as substrate was inhibited by xylitol due to the inhibition of the enzyme D-xylose-isomerase. Experiments with mutants should prove the value of pentose/pentitol utilization as a biochemical character for the identification of S. xylosus and S. saprophyticus . It was possible to isolate pentose-negative mutants of S. xylosus which resemble S. saprophyticus in the pentose/pentitol metabolism, but we did not succeed in isolating pentose-positive mutant of S. saprophyticus . This indicates that degradation of xylose and/or arabinose is a characteristic property fo S. xylosus strains. Pentose-negative mutants of S. xylosus lack activity for the isomerization of pentoses but they are still typical S. xylosus as could be shown by DNA-DNA-hybridization studies. DNA-homology values between wild and mutant strains were about 100%, whereas homology values between these mutant strains and a pentose-negative S. saprophyticus wild type were 35–40% corresponding to values obtained between wild types of S. xylosus and S. saprophyticus .

Parenteral nutrition for the surgical patient. A review of indications and current practice.

Parenteral nutrition for the surgical patient. A review of indications and current practice.

International Symposium on Metabolism, Physiology, and Clinical Use of Pentoses and Pentitols.

International Symposium on Metabolism, Physiology, and Clinical Use of Pentoses and Pentitols.

The respiratory pathways of tobacco leaves infected with potato virus X

In an attempt to define the causes for the increased respiration effected by certain strains of potato virus X (PVX) in tobacco leaves, the oxidative and phosphorylative activities of leaf mitochondrial preparations were studied, as well as the hexose and pentose metabolism of cell-free extracts. No difference was found in mitochondrial activities in preparations from healthy leaves and from leaves infected with the severe ringspot strain at the stage of infection when the respiratory increase was maximal. However, in the cell-free extracts from leaves infected with all four strains of PVX, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase showed substantially increased activity compared to those from healthy control leaves. Phosphoriboisomerase activity was less than that in the healthy controls. Comparison of C6/C1 ratios showed a decrease in both inoculated and systemically infected leaves with all four strains. It is concluded that the previously observed increase in the respiration of PVX-infected tobacco leaves is largely connected with an increase in the activities of the enzymes in the pentose phosphate pathway.

International Symposium on Metabolism, Physiology and Clinical Use of Pentoses and Pentitols

International Symposium on Metabolism, Physiology and Clinical Use of Pentoses and Pentitols

Pentose Metabolism by Candida utilis

Pentose Metabolism by Candida utilis

Pentose Metabolism by Candida utilis

Extract of Candida utilis contains polyol: NAD oxidoreductase which catalyzes the conversion of polyols to the corresponding ketoses. By fractionation with ammonium sulfate and on DEAE-cellulose column chromato-graphy, the purity of enzyme has been increased about 14-fold. The relatively high activity with both xylitol and sorbitol suggests that they may be the natural substances for the enzyme. Evidence suggests that this enzyme relates to the metabolism of D-xylose in Candida utilis.

Pentose Metabolism in Bacteria: CIBA Lectures in Microbial Biochemistry

Medical Journal of AustraliaVolume 1, Issue 18 p. 654-654 Review Pentose Metabolism in Bacteria: CIBA Lectures in Microbial Biochemistry First published: 01 May 1965 https://doi.org/10.5694/j.1326-5377.1965.tb72038.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume1, Issue18May 1965Pages 654-654 RelatedInformation

METABOLISM OF PENTOSES AND PENTITOLS BY AEROBACTER AEROGENES. 3. PHYSICAL AND IMMUNOLOGICAL PROPERTIES OF PENITOL DEHYDROGENASES AND PENTULOKINASES.

Mortlock, R. P. (Michigan State University, East Lansing), D. D. Fossitt, D. H. Petering, and W. A. Wood. Metabolism of pentoses and pentitols by Aerobacter aerogenes. III. Physical and immunological properties of pentitol dehydrogenases and pentulokinases. J. Bacteriol. 89:129-135. 1965.-Four pentulokinases and three pentitol dehydrogenases were purified from Aerobacter aerogenes PRL-R3, and the properties of the enzymes within each family were compared. d-Ribulokinase was purified from cells grown on ribitol, d-arabitol, and xylitol, and from a mutant constitutive for ribitol dehydrogenase; d-xylulokinase, from cells grown on d-xylose and xylitol; l-ribulokinase, from cells grown on l-arabinose; and l-xylulokinase, after growth on l-xylose. Similarly, ribitol dehydrogenase was purified after growth on ribitol, d-arabinose, and xylitol, and from the ribitol dehydrogenase-constitutive mutant. d-Arabitol dehydrogenase was obtained after growth on d-arabitol or d-xylose, and xylitol dehydrogenase was obtained after growth on xylitol. Except for l-xylulokinase, which also had a different S(20) value, the pentulokinases had identical pH optima, K(m) for the ketopentose, and sedimentation constants, and fractionated identically by a number of procedures. These kinases could be distinguished only by their substrate and immunological specificity. Ribitol dehydrogenase and d-arabitol dehydrogenase could be distinguished by several properties, but the properties of xylitol dehydrogenase were always similar to ribitol dehydrogenase. In all cases, individual kinases or dehydrogenases produced by different inducers had identical properties. These data constitute evidence against multiple forms of the same enzyme being produced by different inducers and against the dehydrogenase family containing essentially identical proteins differing only at the active site. For the kinases, three of the four appear to differ only at the active site.

METABOLISM OF PENTOSES AND PENTITOLS BY AEROBACTER AEROGENES. I. DEMONSTRATION OF PENTOSE ISOMERASE, PENTULOKINASE, AND PENTITOL DEHYDROGENASE ENZYME FAMILIES.

Mortlock, R. P. (Michigan State University, East Lansing) and W. A. Wood. Metabolism of pentoses and pentitols by Aerobacter aerogenes. I. Demonstration of pentose isomerase, pentulokinase, and pentitol dehydrogenase enzyme families. J. Bacteriol. 88:838-844. 1964.-Aerobacter aerogenes PRL-R3 is capable of utilizing as sole substrates for energy and growth seven of the eight aldopentoses and all of the four pentitols. Growth upon media containing either d-xylose, l-arabinose, d-ribose, d-arabitol, or ribitol occurred within 24 hr at 26 C. When d-arabinose or l-arabitol were used as growth substrates, growth was complete within 2 days; 4 days were required for growth on d-lyxose or xylitol, and 3 to 4 weeks for growth upon l-xylose. The versatility of this strain of A. aerogenes is due to an ability to synthesize in the presence of appropriate carbohydrates (inducers) families of enzymes which catalyze the metabolism of the carbohydrates (i.e., families of pentitol dehydrogenases, aldopentose isomerases, and pentulokinases). The specificity of induction for members of the enzyme families was found to vary, and cross induction of enzyme activity was common, especially among the pentitol dehydrogenases. Ribitol dehydrogenase activity was detected in extracts of cells grown on all of the above carbohydrates with the exception of d-xylose, l-arabinose, and d-ribose. The ribitol dehydrogenase activity of xylitol-grown cell extracts was fivefold higher than the activity in extracts of ribitol-grown cells.

Pentose Metabolism by Candida utilis

Pentose Metabolism by Candida utilis

Isotopic tracer studies on the biosynthesis of deoxyribose in the rat

SUMMARY The biosynthesis of deoxyribose, in vivo, was studied with NaHIIC03 as a tracer, in normal adult, starved adult, normal newborn, thiamine-deficient adult and bearing rats and in Yoshida ascites-tumor cells. Comparisons of the tracer patterns in ribose and deoxyribose isolated from the nucleic acids of skin and liver suggest that in young tissues the formation of deoxyribose may occur by direct reduction from ribose or via an intermediate common to ribose. The data obtained from the livers of young adults do not support this concept unless the pattern of 14C in the ribose which is the precursor of deoxyribose, is different from that of the ribose isolated from the RNA. The presence of an ascitic tumor in the young adult seems to influence pentose metabolism in the host liver.

Isotopic tracer studies on the biosynthesis of deoxyribose in the rat

The biosynthesis of deoxyribose, in vivo, was studied with NaH14CO3 as a tracer, in normal adult, starved adult, normal newborn, “thiamine-deficient” adult and “tumor bearing” rats and in Yoshida ascites-tumor cells. Comparisons of the tracer patterns in ribose and deoxyribose isolated from the nucleic acids of skin and liver suggest that in young tissues the formation of deoxyribose may occur by direct reduction from ribose or via an intermediate common to ribose. The data obtained from ribose which is the precursor of deoxyribose, is different from that of the ribose isolated from the RNA. The presence of an ascitic tumor in the young adult seems to influence pentose metabolism in the host liver.

Pentose metabolism by cell-free extracts of Oospora lactis

The initial stop of d-xylose metabolism by cell-free extracts of Oospora lactis (Geotrichum candidum L.) involves the reduction of xylose to xylitol by TPNH, followed by the DPN-linked oxidation of xylitol to xylulose. Xylulose is phosphorylated by added ATP, thus entering the respiratory pentose phosphate cycle. Also, d-ribose is reduced by the cell-free extracts in the presence of TPNH. The enzymically formed product, d-ribitol, has been isolated and identified. Little, if any, ribitol DPN-linked oxidation was instead observed. These data are discussed from the point of the utilization of d-ribose by the resting cells of Oospora lactis without any increased oxygen uptake above the endogenous rate.

L-arabinose metabolism by cell-free extracts of Penicillium chrysogenum

The enzymic conversion of l-arabinose to both l-ribulose and l-xylulose by the formation of an intermediate, l-arabitol, has been observed in cell-free extracts of Penicillium chrysogenum. All enzymic products involved in these enzymic steps have been isolated and characterized. This finding emphasizes a common enzymic sequence for the initiation of pentose metabolism by this mold.