A-amylases 5-amylases

Q6 Alpha-amylase (a-amylase) is concerned with the digestion of starch to disaccharides and other products in the gut. The salivary glands also produce a-amylase, the parotid glands producing the greatest amount. 

Salivary alpha-amylase (a-amylase) is the major protein secreted by saliva and is encoded by the Amyl gene on chromosome 1. It is an endoglycohydrolase, which means that it hydrolyzes internal al —> 4 glucoside linkages. Its primary substrate is starch, which is composed exclusively of glucose in two forms, amylose and amylopectin. Amylose is a linear polymer of glucose connected by al —> 4 bonds (Fig. 12.10a). The a-amylase... 

Ammonium hydroxide Ammonium sulfide Amylase Amylase, a-Amylase, p-Amylase, iso-Amylodextrin Amylopectin Amylose... 

Amylase A Amano Cone.. See o-Amylase Amylase DS. See Amylase a-Amylase... 

Mcllvaine buffer at pH 6. The standards should preferably be of the pure enzymes, although a selected batch of pancreatin, previously standardised, may be used, and the most suitable dilutions are —for pure trypsin 1 10,000 and 1 40,000 (freshly prepared ), for pure amylase (a-amylase derived from pancreatic extract must be used) 1 2,000 and 1 8,000 and for pancreatin 1 200 and 1 800. 

Endo-amylase (a-amylase) has a liquefying effect, since the viscosity of a colloidal starch solution decreases rapidly and the iodine color reaction disappears without the appearance of reducing sugars. The reducing effect develops later, in a second phase, when the fragments have been broken down further. Maltose is released in the a-form (the optical rotation drops, however, due to muta-rotation) hence the name of the enzyme. 

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