A new procedure for the determination of transferrinC (TfC) subtypes by isoelectric focusing

Abstract

Isoelectric focusing (IEF) is widely used for the determination of serum protein polymorphisms in forensic investigations. Because of non-genetic heterogeneity of some proteins and of protein-ligand dissociation observed after IEF standardization of procedures is necessary. In this article the authors point out the main difficulties encountered in studying the transferrin subtype polymorphism and describe a new and sensitive method. Two new Tf C subtypes were observed: Tf C4 in North American, Bolivian and Brazilian Indians, Tf C5 in Black Americans, both with polymorphic allele frequencies. In a Pyrenean population the allele frequencies for Tf C1, Tf C2 and Tf C3 were quite similar to those observed in a German population sample.

Genetic polymorphism of transferrin in Egyptians: Analysis by two electrofocusing methods with description of unusual B variant

“…Treatment of the samples with 0.3~ ferric chloride in conjunction with using ampholine pH 5-7 provides certain advantage if the pattern is compared with that observed when the ampholine pH 4-6.5 is used (Weidinger , 1980). In the o t h e r p r o c e d u r e which was originally described by C o n s t a n s et al (1980a), we o b s e r v e d high r e s o l u t i o n with r e p r o d u c i b l e pattern, but the treatm e n t o f sera with ferric chloride described in this study offers a very rapid typing, since it needs 10 min only as compared with 18 hr if the method of Constans et al (1980a) will be used, in addition to the excellent resolution and reproducibility. The distribution of the observed phenotypes is given in Table 1.…”

“…B) Ferrous ammonium sulphate. 5 yl of serum was added to 25 ~1 of 0.25~o ferrous ammonium sulphate x6H~O as described by Constans et al (1980a), and the mixture was incubated in the refrigerator for 18 hr before analysis. Isoelectric focusing.…”

“…On the contrary to the electrophoretic methods, the method of electrofocusing using native sera directly for analysis showed difficulties and problems in reproducibility and sensitivity. Therefore several procedures in which sera are subjected to pretreatment prior to electrofocusing have been described (Stibler et al, 1979;Constans et al, 1980a;Sebetan et al, 1982;Weidinger et al, 1980). This study provides the first data on the transferrin polymorphism among Egyptians.…”

“…The use of isoelectric focusing for analysis of the transferrin variants has revealed five common transferrin C suballeles (Kiihnl and Spielmann, 1979;Constans et al, 1980a). The most common suballeles, Tf ca and Tf c2, have been observed in all the tested populations (Thymann, 1978;Hoste, 1979;Stibler et al, 1979;Kueppers and Harpel, 1980;Constans et al, 1980a, b;Sebetan et al, 1982), while the rest of the suballeles seems to occur in certain populations (Constans et al, 1980a). The products of the five suballeles are in the order of C4, C1, C3, C5 and C2 from anode to cathode.…”

Electrophoretic variants of blood proteins in Japanese VI. Transferrin

“…Since Ktihnl and Spielmann (1978) and Thymann (1978) succeeded in separating subtypes of TF C, which cannot be separated by SGE, by employing polyacrylamide gel isoelectric focusing (PAGIF), at least seven subtypes have been detected and all of them have been identified as allelic variants (Constans et al, 1980;Dykes et al, 1982;Kamboth and Kirk, 1983;Pascali and Auconi, 1983). However, there is only one report which compares variants detected by SGE using PAGIF (Kiihnl et al, 1979).…”