Carbohydrates, degradation

A second family of carbohydrate-degrading enzymes, the lysozymes, produces synergistic antimetastatic activity when co-adrninistered with cisplatin [15663-27-1] to mice whose primary tumor had been surgically removed (51). 

Kohlenhydrat, n. carbohydrate, -abbau, m. carbohydrate degradation, specif, carbohydrate catabolism, -stoffwechsel, m. carbohydrate metabolism, -verwertung, /. carbohydrate utilization. 

Exoglycosidases that are useful in carbohydrate degradations include neuraminidases, fucosidases, galactosidases, mannosidases, and aminohexosidases.76,77 An example of the use of degradation by a gly-cosidase in conjunction with methylation analysis is a study on the oc-... 

Recovery of inorganic chemicals is crucial to the cost effectiveness of the Kraft process. The black liquor which is obtained from delignification is rich in solubilised lignin and carbohydrate degradation products and, after concentration, is combusted in a recovery furnace. The Carbon dioxide which is produced during combustion converts unused sodium hydroxide into sodium carbonate. In addition, the sodium sulfate is converted, under the reducing atmosphere of the furnace, to sodium sulfide. 

Both the aldol and reverse aldol reactions are encountered in carbohydrate metabolic pathways in biochemistry (see Chapter 15). In fact, one reversible transformation can be utilized in either carbohydrate biosynthesis or carbohydrate degradation, according to a cell s particular requirement. o-Fructose 1,6-diphosphate is produced during carbohydrate biosynthesis by an aldol reaction between dihydroxyacetone phosphate, which acts as the enolate anion nucleophile, and o-glyceraldehyde 3-phosphate, which acts as the carbonyl electrophile these two starting materials are also interconvertible through keto-enol tautomerism, as seen earlier (see Section 10.1). The biosynthetic reaction may be simplihed mechanistically as a standard mixed aldol reaction, where the nature of the substrates and their mode of coupling are dictated by the enzyme. The enzyme is actually called aldolase. 

The relationship, if any, between the secondary metabolism of L-phenylalanine and carbohydrate degradation during brown-rot wood decay processes has not yet been determined. However, we suspect that the secondary metabolism of this aromatic amino-acid plays an important role in converting monomeric sugars to nitrogen-free metabolites (Shimada, M., and Takahashi, M., In Handbook of Wood and Cellulosic Materials Hon,... 

Correct answer = E. The physical symptoms sug gest a deficiency in an enzyme responsible for carbohydrate degradation. The symptoms observed following the ingestion of dairy products suggest that the patient is deficient in lactase. 

Fig. 20.1. Generalized scheme of the main pathways of aerobic and anaerobic carbohydrate degradation in parasitic flatworms. The aerobic pathway is indicated by open arrows, whereas the anaerobic pathway (malate dismutation) is indicated by solid arrows. Abbreviations AcCoA, acetyl-CoA ASCT, acetateisuccinate CoA-transferase C, cytochrome c CI-CIV, complexes I—IV of the respiratory chain CITR, citrate FRD, fumarate reductase FUM, fumarate MAL, malate Methylmal-CoA, methylmalonyl-CoA OXAC, oxaloacetate PEP, phosphoenolpyruvate PROP, propionate Prop-CoA, propionyl-CoA PYR, pyruvate RQ, rhodoquinone SDH, succinate dehydrogenase SUCC, succinate Succ CoA, succinyl CoA UQ, ubiquinone.

Formaldehyde, along with other short-chain aldehydes such as acetaldehyde, is a low molecular weight, volatile, reactive contaminant that can be present at low levels from a variety of sources (e.g., excipients such as polyethylene oxide, polyethylene glycol (64,65), or from carbohydrate degradation (66), solvent contamination (51), packaging materials (52), etc.). Formaldehyde is known to react with amines (Fig. 33) to form a reactive N-hydroxymethyl compound (a hemiaminal) that can further react with other nucleophiles. Reaction of formaldehyde with amino acids (67) can cause... 

For another reaction, i.e. Ruff s carbohydrate degradation [46], the origin of the true oxidant is also unclear. The reaction between a-oxyacids and H202 in the presence of trivalent ferric salts is presented by the following overall reaction ... 

The pyrolysis of oligosaccharides such as cellulose and related products has provided a good understanding of how complex carbohydrates degrade thermally (39-491. Interestingly, most of this research was centered around the development of flame retardants for building materials. 

Molasses. A large number of volatile and nonvolatile compounds have been identified in the flavor fractions of various types of molasses (51-621. Compound classes identified include aliphatic and aromatic acids, aldehydes, phenols, lactones, amines, esters, furans, pyrazines, and sulfides. Most of these compounds can arise from carbohydrate degradation through a number of traditional pathways especially because residual nitrogen-containing sources are present. 

Figure 1 Suggested reaction routes of carbohydrate degradation via the 1-deoxyosone...

To test whether Acp was formed at such proline concentrations, dilute aqueous model solutions of proline were boiled in the presence of various sugars or phosphorylated compounds known to be metabolites of carbohydrate degradation in yeast (9). The results, summarized in Table IV showed that neither heating of proline alone (No. 1) nor in the presence of glucose, fructose or sucrose (No. 

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