Mammalian cells have developed multiple enzymatic pathways for HNE detoxification.
Synthesis of glycocalyx is complex, involving multiple enzymatic pathways; factors regulating its shedding include local pH and mechanical stimuli [ 12].
In some cases (for example, congenital metabolic diseases), it may be possible to identify a single, robust diagnostic metabolite, but in many cases the perturbations are more subtle, involving the activation of multiple enzymatic pathways.
Different signal transduction pathways are simultaneously activated by VEGFR VEGF complexes with membrane trafficking along the endosome lysosome network further modulating signal output from multiple enzymatic events associated with such pathways.
Because of the ability to control multiple, if not all steps in a particular metabolic pathway, TFs provide attractive tools for overcoming flux bottlenecks involving multiple enzymatic steps, or for deploying pathway genes in specific organs, cell types or even plants where they normally do not express.
The cholesterol biosynthetic pathway comprises multiple enzymatic steps leading to cholesterol biosynthesis and these genes are coordinately up-regulated by IGF-1 (Fig. 2 and Table 4).
Only approximately 150 proteins are known to be GPI-anchored, and the GPI synthetic pathway, involving multiple enzymatic steps in the ER (endoplasmic reticulum) and Golgi, is likely to have limited capacity in mammalian cells [ 52].
Although multiple enzymatic steps and the regulatory hierarchy in the pathway limit the rate of galactose utilization and the simultaneous fermentation of many carbohydrates [ 21], the reconstruction of galactose pathway on chromosome enhanced the galactose utilization rate and the simultaneous assimilation of galactose and glucose [ 10].
During the past dozen years, the Rutgers group has uncovered multiple spectral signatures for intermediates along the ThDP-dependent enzymatic pathways.
However, it is obvious that this approach requires simplifying assumptions in relation to the relative contribution of multiple enzymatic systems to metabolism and the extent of inhibition or induction of these pathways due to co-exposures and other environmental factors [ 89], and accordingly the outcome of uncertainty factor estimations should be regarded with caution.
PI3-K regulates diverse cellular functions such as growth, survival and malignant transformation through its multiple enzymatic functions, namely lipid kinase and protein kinase activities [ 30, 31], and acts either synergistically with the Raf pathway [ 32] or in opposition to it [ 33].
