AMINO-ACID-ANALYSIS OF A TUMOR-ASSOCIATED ANTIGEN ISOLATED FROM THE TUMOR-TISSUE OF COWS WITH ENZOOTIC BOVINE LEUKOSIS

A tumour-associated antigen (TAA) expressed in tumour cells of cattle with enzootic bovine leukosis (EEL) was isolated from the tumour tissu e of cows serologically and haematologically positive for EEL and path o-anatomically and histologically positive for lymphosarkcomatosis of the prolymphocytic type. After homogenisation, ultrasound disintegrati on and ultrahighspeed centrifugation of the tumour tissue, the glycopr oteins of the supernatant were extracted using perchloric acid and the TAA was purified by gel filtration and successive SDS-polyacrylamide electrophoresis. The molecular weight of the TAA was estimated to be 7 0.000 D. By aminoacid analysis the total aminoacid content of TAA was found to be 5,935 mmol/g. The proportion of particular aminoacid group s was as follows: 74,8% neutral amino acids, 14,4% acidic amino acids, and 10,8% basic ones. Compared with non-tumour fractions the tumour f ractions contained elevated amounts of glycine, alanine, isoleucine, l eucine, and lysine.