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DISTINCT MOLECULAR SPECIES OF HUMAN α‐FETOPROTEIN DUE TO DIFFERENTIAL AFFINITIES TO LECTINS a
Author(s) -
Taketa Kazuhisa,
Izumi Masaki,
Ichikawa Eriko
Publication year - 1983
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1983.tb32849.x
Subject(s) - affinities , chemistry , affinity electrophoresis , lectin , thiourea , affinity chromatography , human serum albumin , dissociation constant , concanavalin a , biochemistry , enzyme , in vitro , receptor , organic chemistry
Resolution of human alpha-fetoprotein (AFP) into four distinct molecular species was demonstrated by a combination of two affinity chromatographies with crossed-immuno-affino-electrophoresis (CIAE) using concanavalin A (Con A) and Lens culinaris hemagglutinin (LcH)-A and LcH-B as affinity media. Of the four AFPs, AFP1 had no affinity for Con A, LcH-A, or LcH-B; AFP2 showed a high affinity for Con A, a low affinity for LcH-A, and an intermediate affinity for LcH-B (or a low affinity, depending on the lot of LcH-B preparations used); AFP3 revealed strong affinities for all of the three lectins; and AFP4, a trace component of hepatoma AFP in the present study, showed no interaction with Con A, but a definite interaction with LcH-A or LcH-B. These results were based on the determination of dissociation constants (Kd) of AFP-lectin complex by CIAE on isolated preparations of the three major hepatoma AFPs. These AFPs had identical electrophoretic mobilities of 0.86-0.87 (relative to human albumin) in the absence of lectins. The calculated mobilities of AFP2 and AFP3 were both reduced to 0.50-0.58 by saturation with lectins, but these two AFPs were clearly separated by 1 mg/ml LcH-A or LcH-B because of their large differences in Kd.