A-Amy lase

The process starts in the mouth during mastication where salivary a-amy-lase cleaves some of the a-1,4 glycosidic bonds of starch. 

Velanakar, S. and Murthy, M. R. N. (1984). Studies on molecular evolution and structural features of double headed inhibitors of a-amy lase and trypsin in plants.. Genet. 73,43-54. 

The pancreas also secretes a number of enzymes in tfcfii c/on , including a-amy-lase, lipase, deoxyribonuclease (DNase), and ribonuclease (RNase). DNase catalyzes the hydrolysis of DNA, resulting in the liberation of deoxyadenosine monophosphate (dAMP), dcoxythymidine monophosphate (dTMP), deoxyguanosine monophosphate (dGMP), and deoxycytosine monophosphate (dCMP). 

E466 Nealon, D.A. (1988). The New York State proficiency testing program a-amy-lase methodology and proficiency. Clin. Chem. 34,1246-1247, Abstr. 459. 

G.A3 activates genes in barley from which the embryo has been removed, suggesting that the embryo releases G. into the aleurone layer, where it activates the genes for hydrolytic enzymes, particularly a-amy-lase. Another test for G., the a-amylase test, is based... 

Studies on the early responses of aleurone layers to GA have shown that a-amy-lase is not the first enzyme to be secreted. Within 5 h of the addition of GA to isolated aleurone layers of barley (cv. Betzes) there is increased secretion into the surrounding medium of several hydrolytic enzymes, including an ATP-ase, phytase, j -glucosidase and phosphomonoesterase, as well as some soluble carbohydrate [96] (probably sucrose). Similar observations were made using GA-treated half-grains of both barley and wheat (the distal embryoless half), although in barley additional enzymes, e.g. an esterase, phosphodiesterase and a-galactosidase were also found to be secreted early [96]. From the limited information available to date it appears that some enzymes which are secreted early after GA addition (e.g. phosphomonoesterase and phosphodiesterase) do so in response to lower concentrations of GA than do the later ones (e.g. a-amylase) [97]. Furthermore, a-amylase and proteinase, which are secreted simultaneously, have identical GA dose-response curves (Fig. 7.5A and B). There are exceptions, however, and further work on more enzymes is required to determine if the sequence of enzyme production by aleurone tissue is related to GA concentration in the cells. 

These latter synthesize ptyalin, an endoamylase which is also an a-amy-lase. When we come to the gastric mucosa, besides mucous cells we find present parietal cells specialized for the secretion of hydrochloric acid by a mechanism of active transport, and peptic cells which can synthesize pepsinogen, from which an endopeptidase, pepsin, is formed. 

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