Immunochemical Studies on Structural Proteins of the Red Cell Membrane.

1. Tryptic hydrolysates of denaturated glutamic-aspartic transaminase fractionated on a Sephadex G-25 column, gave an elution diagram containing six main fractions. When peptide maps were developed from the transaminase digest 37 spots were detected on the paper sheet. 2. It was demonstrated that the transaminase fractions (groups of peptides) as well as some of the individual peptides eluted from the map spots, possessed immunological activity. This was proved by theft capacity to interact with rabbit pig heart antienzyme and rabbit antiserum against the pig-heart whole tryptic transaminase hydrolysate as well as to inhibit the homologous transaminase-antitransaminase reaction. Higher immunological reactivity was found among peptides moving faster in electrophoresis and chromatography. 3. The catalytic activity of rabbit transaminases (heart, liver, skeletal muscles), was inhibited to a substantial degree by the rabbit anti-pig heart transaminase. The above enzymes however. as was otherwise expected, gave negative precipitin reactions with antitransaminase. A comparative study of the reactivity between transaminases from pig, ox and rabbit and rabbit antitransaminases against pig and ox heart enzymes as well as against pig-heart whole tryptic transaminase hydrolysate is presented here. [ABSTRACT FROM AUTHOR]