Transaminases of Tapeworms

Abstract

Although transaminases were identified in animal tissues as early as 1937, very few observations have been made on these systems in parasitic helminths. Daugherty (1952) found that homogenates of the liver fluke, Fasciola hepatica, contained very high transaminase activity. Using the formation of glutamic acid from alphaketoglutaric acid as an indication of transaminase, Daugherty demonstrated the utilization of 11 of 13 amino acids tested as amino donors. The quantity of glutamic acid formed was high when aspartic acid, isoleucine, leucine ,and valine were used; the activity was moderate with arginine, alanine, phenylalanine, tyrosine, methionine, and proline. Tryptophan gave questionable results, and lysine and cystine were inactive. In contrast to the high transaminase activity of liver fluke homogenates, Aldrich, Chandler, and Daugherty (1954) found the activity of homogenates of the tapeworm, Hymenolepis diminuta, to be relatively low, only a few amino donors being effective. In 3 systems, alpha-ketoglutaric acid-glutamic acid, pyruvic acid-alanine, and oxalacetic acid-aspartic acid, only 3 amino acids, aspartic acid, glutamic acid, and alanine were effective as amino donors.