Bacteria metabolic pathways

Histidine phosphatases and aspartate phosphatases are well established in lower organisms, mainly in bacteria and in context with two-component-systems . Reversible phosphorylation of histidine residues in vertebrates is in its infancy. The first protein histidine phosphatase (PHP) from mammalian origin was identified just recently. The soluble 14 kD protein does not resemble any of the other phosphatases. ATP-citrate lyase and the (3-subunit of heterotrimeric GTP-binding proteins are substrates of PHP thus touching both, metabolic pathways and signal transduction [4]. 

Chapman PJ, DW Ribbons (1976) metabolism of resorcinylic compounds by bacteria alternative pathways fore resorcinol catabolism in Pseudomonas putida. J Bacterid 125 985-998. 

Watson K, RB Cain (1975) Microbial metabolism of the pyridine ring. Metabolic pathways of pyridine biodegradation by soil bacteria. Biochem J 146 157-172. 

Biochemical reactions. Biochemical reactions, often referred to as fermentations, can be divided into two broad types. In the first type, the reaction exploits the metabolic pathways in selected microorganisms (especially bacteria,... 

In summary, two general pathways are now accepted as the reaction basis of pyridine degradation by bacteria. One involves (i) hydroxylation reactions, followed by reduction, e.g., on Bacillus strain 4 and the other (ii) (aerobic) reductive pathway(s) not initiated by hydroxylations, e.g., on Nocardia strain Zl [348], Two review articles, one by Kaiser [320] and the other by Fetzner [326] gave the complete microbial metabolic pathways for several nitrogen compounds carried out in the presence of a variety of microorganisms, some of them previously studied by Professor Lingens [349], The complete degradation pathways of pyridine are shown in Fig. 29. 

Nicotinic acid derivatives occur in biologic materials as the free acid, as nicotinamide, and in two coenzymatic forms nicotinamide adenine dinucleotide (NAD), and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes act in series with flavoprotein enzymes and, like them, are hydrogen acceptors or, when reduced, donors. Several plants and bacteria use a metabolic pathway for the formation of nicotinic acid that is different from the tryptophan pathway used by animals and man (B39). 

Metabolism via normal metabolic pathways or fast excretion without metabolism are desirable characteristics. Some intense sweeteners are excreted unchanged while others are metabolised. Bulk sweetener absorption is lower and slower than for carbohydrates and results in reduced caloric availability which is partly due to metabolites formed by intestinal bacteria. Such metabolites and osmotic effects of not fully absorbed bulk sweeteners can cause laxative effects. Generally, the calorific value of bulk sweeteners is lower than for carbohydrates. Intense and bulk sweeteners are, as far as they are metabolised, not dependent on insulin. They are therefore acceptable for diabetics as part of a suitable diet. 

Antibacterial sulfonamides contain two N-atoms, the sulfonamido (N1) and the para primary amino (N4). The sulfonamido group, in contrast to a carboxamido group, is chemically and metabolically stable. In other words, hydrolytic cleavage of sulfonamides to produce a sulfonic acid and an amine has never been observed. We, therefore, focus our discussion on the primary amino group, acetylation of which is one of the major metabolic pathways for some sulfonamides. Hydrolysis of the N4-acety luted metabolites back to the parent sulfonamide can occur in the liver, kidney, and intestinal tract. The reaction is strongly influenced by the structure of the parent amine e.g., N4-acetylsulfisoxazole (4.121) was deacetylated by intestinal bacteria whereas /V4-acctyIsulI anilamide (4.122) under identical conditions was not [78][79],... 

Ormerod, J.G., Gest, H. 1962. IV. Hydrogen photosynthesis and alternative metabolic pathways in photosynthetic bacteria. Bacteriol Rev 26 51-66. 

L-Rhamnose isomerase catalyzes the interconversion of L-rhamnose and L-rhamnulose. L-Rhamnose, a deoxy sugar, is found in bacteria and plants and it plays an essential role in many pathogenic bacteria. The pathway for the metabolism of this sugar does not exist in humans, and this makes enzymes of this pathway attractive targets for therapeutic intervention. " Rhamnose isomerase from E. coli is a tetramer of (/ /a)8-barrels similar to xylose... 

An attractive hypothesis is the independent evolution in bacteria of their diffusible individualites and the currently recognized secondary metabolic pathways, in parallel with their surface components and their biosynthesis. An indicator for this would be the use of the same gene pool. The theory would include all substances that play a role in the build-up of glycan and other modified surface layers, lipids, murein, (glyco-) proteins (e.g., S-layers), polysaccharides, teichoic... 

Scheme 23.5 Metabolic pathways of lactic acid bacteria leading from pyruvate to a-acetolactate and acetoin and chemical diacetyl formation. ALS a-acetolactate synthase, ALDB a-acetolactate decarboxylase, DDH diacetyl dehydrogenase. (Adapted from [72])...

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