Abstract
Chromatographically purified fractions of aqueous-ethanolic extracts from Baptisia tinctoria roots contained a strong lymphocyte DNA synthesis-stimulating activity. Electrophoretic
analysis of these fractions revealed four distinct protein bands with molecular masses
of P 1 = 58 kD; P4 = 31 kD; P 5 = 26 kD; and P 6 = 14 kD. They contained carbohydrate
as determined by periodic acid Schiff staining. An estimation of the approximate amount
of sugar was done by using human transferrin as a reference, this method revealed
the following values: P 1 = 27%; P 4 = 12%; P 5 = 14%; and P 6 = 8%. The mixture of
proteins and every single band were immunoreactive with a polyclonal antiserum against
Baptisia proteins determined in immune and dot blots, respectively. Electrophoretically purified
proteins were characterized by tryptic cleavage and determination of their amino acid
content. They contained several common amino acids, predominantly aspartic acid, glutamic
acid, threonine, and alanine. The content of glucosamine and/or galactosamine was
less than 0.2 Molper cent. The four proteins revealed pi values between 5.3 and 4.7.
Protein P 4 was immunochemically related to phytohemagglutinin but, in contrast to
PHA-P, it exhibited no hemagglutinating activity and no leucagglutinating activity
like PHA-L.
