Phenotypic variation of human antithrombin III in normal plasma: Detection by isoelectric focusing

Abstract

SummaryPlasma AT-III exhibits a microheterogeneous form with pls distributed over a narrow pH range by analytical agarose gel isoelectric focusing followed by immunofixation. Three new variants, each of which was the heterozygous state between the common and each variant components, were observed in a total 370 samples from unrelated healthy donors. These variants have at least normal activities of the thrombin inactivation in the presence of heparin, and their immunological antigen concentrations in plasma are in the normal range.

Two-dimensional gel studies of genetic variation in the plasma proteins of Amerindians and Japanese

“…No variants of this polypeptide were encountered in either of the two populations, in contrast to the finding of a low-frequency polymorphism in Caucasoids. Kera et al (1983), employing analytical agarose gel isoelectric focusing followed by immunofixation, encountered one instance each of three different antithrombin III variants in 370 Japanese samples. The studies necessary to determine if these variants would be detected in our system have not been performed.…”

Genetic studies of low abundance human plasma proteins VIII. Inherited structural variation in antithrombin III

“…Recently rare structural variation in AT I11 has been observed using isoelectric focusing (IEF) followed by immunofixation (Weidinger et aZ. 1983;Kera et al 1983;Milner et al 1985). In contrast to the reported variation in these communications, we present evidence for the existence of common polymorphism a t the AT 111 structural locus, using a more sensitive method of IEF in an ultra narrow pH gradient containing 6 M urea and detection by immunoblotting.…”

“…immunoelectrophoresis (Sas et al 1975 ;Leone et al 1983Leone et al , 1986). Kera et al(1983) and Weidinger et al (1983) have claimed to observe different structural mutant forms of AT I11 at extremely low frequencies in Japanese and Germans, respectively. However, their claims were not substantiated by family data, except that Weidinger et al (1983) could demonstrate that one variant out of the proposed five segregated in a limited number of families.…”

“…As is the case with other glycoproteins, the basis of this heterogeneity appears to be the presence of terminal residues of sialic acid on the carbohydrate side chains. In this context, Kera et al (1983) and Milner et al (1985) observed that neuraminidase treatment reduced the microheterogeneity but did not completely abolish it. However, Daly & Hallinan (1983) noted that, in order to remove sialic acid completely, an exhaustive neuraminidase treatment was necessary.…”

“…Kera et al 1983; Weidinger et al 1983;Milner et al 1985), IEF-immunoblotting(Daly & Hallinan, 1985) or crossed gel…”