Cascade glycerol

Fig. 13.6 A m ulti-enzyme one-pot example cascade conversion of glycerol into a heptose sugar through consecutive phosphorylation, oxidation, aldol reaction and dephosphorylation [11],...

Another interesting case is the one-pot four-enzyme cascade conversion of glycerol into a heptose sugar on gram scale [11], in which a pH switch method is applied to temporarily turn off one of the enzymes involved (Fig. 13.6). The four consecutive enzymatic conversion steps in one and the same reactor, without separation of intermediates, consist of ... 

The same as above holds for the (by-product) glycerol, a really challenging molecule for cascade conversions in water. 

Extracellular epinephrine (adrenaline) (from the adrenal medulla) activates /33-adrenergic receptors on fat cells to induce the breakdown of triacylglycerols to free fatty acids and glycerol. The intracellular enzyme involved in this process, hormone-sensitive lipase, is activated by protein kinase A. What are the key elements of the signal transduction cascade ... 

Maccarrone M, Salvati S, Bari M, Finazzi-Agro A (2000b) Anandamide and 2-arachidonoyl-glycerol inhibit fatty acid amide hydrolase by activating the lipoxygenase pathway of the arachidonate cascade. Biochem Biophys Res Commun 278 576-583... 

When certain hormones bind to their receptors in adipose tissue, a cascade mechanism releases fatty acids and glycerol from triacylglycerol molecules. Triacylglycerol lipase (sometimes referred to as hormone-sensitive lipase) is activated when it is phosphorylated by protein kinase. Protein kinase is activated by cAMP. After their transport across the plasma membrane, fatty acids are transported in blood to other organs bound to serum albumen. 

In most bio-bio examples two enzymes are applied but four examples already exist where eight enzymes operate in concert. Cascade record holder is a 12-slep synthesis of hydrogenobyrinic acid, the corrin moiety of vitamin B12, starting from 5-aminolevulinic acid [19], An example in which enzymes are switched on and off by pH variation is the four-step one-pot synthesis of ketoses from glycerol [20]. It may be noted that a modern laundry detergent formulation contains up to six different enzymes. 

MonoSik, R., Ukropcova, D., Stredansky, M., and Sturdik, E. (2012) Multienzy-matic amperometric biosensor based on gold and nanocomposite planar electrodes for glycerol determination in wine. Anal. Biochem., 421, 256-261. Bruggink, A., Schoevaart, R., and Kieboom, T. (2003) Concepts of nature in organic synthesis cascade catalysis and multistep conversions in concert. Org. Process Res. Dev., 7, 622-640. 

Schoevaart, R., van Rantwijk, F., and Sheldon, R.A. (2000) A four-step enzymatic cascade for the one-pot synthesis of non-natural carbohydrates from glycerol. J. Org. Chem., 65, 6940-6943. 

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