Isoamylase Pattern Research Articles

Isoamylases in Blood, Urine, and Tissue Homogenates from Some Experimental Mammals

The isoamylase patterns of the serum, urine, and various tissue extracts of some mammalian species were studied with the aid of agarose gel electrophoresis followed by incubation with a starch-dye polymer. In the dog and cat mainly one fraction of amylase, derived from the pancreatic gland, was found in the serum and in the urine. In the rabbit, identical isoamylases were produced by the salivary and pancreatic glands and possibly also by the duodenum; they were detectable in serum and were excreted in the urine in partly changed form. In the rat, the salivary isoamylase was clearly differentiated from the pancreatic isoamylases in serum and urine. Skeletal muscle also produced a starch-degrading enzyme, but no conclusive evidence of hepatic amylase production was found. In the mouse, the salivary and pancreatic isoamylases of serum and urine were clearly separated. Evidence of amylase production was found in the liver and duodenum. These amylases belonged to the pancreatic group of isoamylases. In the guinea-pig, the salivary and pancreatic isoamylases differed from one another in their electrophoretic migration rates; in the serum and urine only salivary isoamylases were detectable. In the Golden Syrian hamster, the salivary glands, the pancreatic glands, and the small intestine-fallopian tube differed from each other in respect of the groups of isoamylases they produced. The pancreatic isoamylase was never seen in the serum or the urine.

Use of Serum Amylase Isoenzymes in Evaluation of Pancreatic Function

Amylase isoenzyme patterns were evaluated in serum, urine, and duodenal fluid from 19 patients with cystic fibrosis (CF) and normal subjects. Two thirds of the CF patients with absent pancreatic enzymes lacked a serum pancreatic isoamylase band, while the remainder had a markedly diminished pancreatic band when compared to the salivary isoamylase. In normal sera the pancreatic band is equal to or greater than the salivary band. In all patients with absent enzymes the diagnosis of abnormal pancreatic function could have been made by evaluation of serum isoamylase patterns thereby avoiding duodenal intubation or collection of 72-hour stools for proteolytic enzyme activities. The patients with normal pancreatic enzyme activities had normal serum zymograms. No CF patient had a low total serum amylase concentration. Total duodenal fluid amylase levels may be misleading in the evaluation of pancreatic function since the amylase may be of salivary origin. The advantages of this isoamylase method include (1) simplicity and noninvasiveness, requiring only a small blood sample; (2) specificity for pancreatic function; and (3) independence of pancreatic enzyme medication.

Affinity Characteristics of Amylase-Binding Substance(s) Prepared from Macroamylase Complexes

Abstract Partially purified macroamylase complexes, subjected to chromatography at pH 3.4, were partly or completely dissociated in each of the 30 sera so studied. The protein fractions contained variable quantities of residual undissociated macroamylase. They also contained binding substance(s), as evidenced by ability to bind added amylase. Pancreatic and salivary amylase were separately mixed with each preparation of binding substance(s) and chromatographed. Binding affinity, measured by the activity of newly formed macroamylase, varied considerably. Most of the binding substances bound considerably more salivary than pancreatic amylase; none showed markedly greater affinity toward pancreatic than toward salivary amylase. By and large, there appeared to be an association between the isoamylase pattern of the amylase released from the macroamylase complexes at pH 3.4 and the relative binding affinities of the binding substances toward pancreatic and salivary amylases.

The origin of serum amylase. Electrophoretic studies of isoamylases of the serum, liver and other tissues of adult and infant rats.

Abstract To obtain information on the tissue origin of serum amylase, partially purified preparations of rat liver and serum amylase and extracts of various tissues were subjected to cellulose acetate electrophoresis followed by detection of the amylolytic activity of starch-agar plates. A method is described for the 600-fold purification of detergent-solubilised liver amylase. The pancrease showed three bands of amylase activity migrating towards the cathode, while the parotid gland revealed five to six anodic bands. In adults rats, the serum and urine showed isoamylase patterns which were the same as those of the liver, and similar to those of the parotid. Isoamylases of the pancreatic type appeared in the serum and urine only after ligation of the commone bile duct. In newborn rats, the serum and liver contained isoamylases of the pancreatic as well as parotid type but the pancreatic type disappeard from both serum and liver by the third day after birth. There was a 100-fold increase in the levels of parotid gland amylase after weaning, which was not reflected in the levels of serum amylase. These results support the view that the liver is the major source of serum amylase in the normal rat.

Isoenzyme variation of human salivary amylase.

Variation of human salivary amylase was investigated by immunofixation electrophoresis. Preliminary data disclosed 16 different isoamylase variants in a total frequency of about 15%. More than 1 gene locus may determine the salivary isoamylase pattern.