The amylase gene-enzyme system of chickens. II. Biochemical characterization of allozymes

The chicken amylase allozymes, AmyF and AmyS, were extracted from pancreatic tissues of AmyF/F and AmyS/S individuals and purified. Activities were measured under various reaction conditions (= treatments) to assess whether the allozymes were functionally different. The amylases had properties typical of alpha-amylases, i.e., both were inhibited by ethylenediaminetetraacetate and alpha-amylase inhibitor from wheat, had pH optima between 7.0 and 8.0, and could utilize a variety of substrates containing alpha 1,4 linkages. The amylases were also found to be inhibited by potassium phosphate buffer and p-chloromercuribenzoate. In terms of substrate specificity, both amylases could utilize all of the substrates tested with activity observed in the following order: amylopectin greater than potato starch greater than dextrin greater than glycogen greater than amylose. Statistical analysis indicated significant functional differences between the two allozymes in terms of specific activities, substrate specificities, and inhibitor sensitivities. AmyF had a significantly lower specific activity than did AmyS. The amylases responded differently to the substrate amylose, with AmyF better able to digest this substrate. AmyS was less sensitive than AmyF to alpha-amylase inhibitor from wheat.

Distribution of alpha-amylase activity in selected broiler tissues

In an examination of broiler alpha-amylase, significant variation in the serum enzyme activity level was noted, adult levels were lower than those of young chicks. Analysis of alpha-amylase activity in various body fluids and tissues of 11-day and 7-week-old broilers indicated that the liver cannot be considered a source of alpha-amylase, although there was activity in both liver tissue and bile of 10 units/g wet weight and 35 units/100 ml, respectively. Fluid from the oral cavity had low levels of alpha-amylase activity, less than 100 units/100 ml, which decreased with age, indicating that the salivary glands may synthesize some alpha-amylase but are not a primary source. Sonication of the pancreatic homogenates was found to significantly increase the apparent activity of alpha-amylase 35-fold over unsonicated homogenates. The pancreas was the major source of alpha-amylase with activities ranging from 89 X 10(2) to 445 X 10(2) units/g wet weight. The level of activity increased with age of the bird. The electrophoretic zymograms of serum, liver, and pancreatic homogenates indicate a similar pancreatic origin for the alpha-amylase found in each tissue or fluid.