Comparing Pathways

If a primary pathway is mapped onto a reference pathway, the system interprets the mapping in the following manner  

Mapping a set of metabolites from one species onto a pathway created with another species, would allow one to see which metabolites are identical and which are missing. A diagram template may also be used to create a default pathway. As mentioned before, each pathway keeps its own information about the position of metabolites, and each created pathway may serve as basis for a template. A pathway diagram needs to be printable and easily transferred to a report container, such as a document. Finally, a pathway diagram may be exported either as image or in XML format including the structure (connection tables) and connectivity information of the molecules. 

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A formally comparable pathway is used by a strain of Alcaligenes sp. that degrades 4-hydroxyacetophenone to 4-hydroxybenzoyl methanol, which is oxidized in an unusual reaction to 4-hydroxybenzoate and formate. The 4-hydroxybenzoate is then metabolized to 3-ketoadipate via 3,4-dihydroxybenzoate (Figure 8.35b) (Hopper et al. 1985). 

A comparable pathway was used by Arthrobacter sp. strain TM-1, which was able to grow with 4-chlorobenzoate and 4-bromobenzoate (Marks et al. 1984). 

Comparable pathways may bring about dehalogenation of phenols with other para-halogen substituents ... 

The advantage of subcellular compartments is that a specific pathway can be isolated from comparable pathways that might use similar or identical chemical intermediates. Compartmentalization simplifies regulation of the various processes. 

Phenols carrying five substituents may be degraded by comparable pathways. 

During the degradation of 4-nitrobenzoate by C. acidovorans, 4-nitroso and 4-hydroxylaminobenzoate were formed successively, and the latter was then metabolized to 3,4-dihydroxybenzoate with the elimination of NH4+ (Groenewegen et al. 1992). It should be noted that these cells were not adapted to growth with either 4-ami-nobenzoate or 4-hydroxybenzoate that are alternative plausible intermediates. A comparable pathway is used by strains of Pseudomonas sp. for the degradation of 4-nitrotoluene that is... 

Uronic acid azides constitute important precursors for A -glycosyl amino acids and their various peptide derivatives, and may be formed by a comparable pathway. Thus, the treatment of acetyl-protected uronic acid esters with tri-methylsilyl azide and SnCU gives the desired acetylated 1,2-trans methyl (o-glycopyranosyl azide)uronates in crystalline form. " Whereas the yields for the gluco 61 and galacto derivatives 62 are satisfactory, the manno analog 63 was obtained in only 11 % yield. Even with an excess of trimethylsilyl azide, the results could not be improved. ... 

The HO radical-initiated atmospheric oxidation of 2,7-dimethyl naphthalene (27DMN) has been investigated at BBIK and G3MP2-RAD//BH HLYP levels. The adduct Rl is formed by addition of HO to the C(l) position and reacts with atmospheric O2 via two slow comparable pathways consisting of direct H abstraction... 

The first steps of the [ C]squalene synthesis resemble the pathway selected for the synthesis on [3 - C]coenzyme QIO 13061 (Figure 6.84). In this case alkylation with solanesyl bromide (3011 and subsequent hydrolysis and decarboxylation of the ester function converted ethyl [3- C]acetoacetate into [2- C]solanesylacetone 302. Chain extension of 302 in a Homer-Wadsworth-Emmons reaction, reduction of the resulting a,/3-unsatu-rated ester 303 and coupling of the resulting alcohol ([3- C]decaprenol, 3041 to 2-methyl-5,6-dimethoxy-1,4-hydroquinone (3051 provided the coenzyme in an overall radiochemical yield of 8% after oxidation. Methodologically comparable pathways have also been published for the synthesis of [5- C]farnesylacetic acid and [3 - C]menaquinone . 

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