Subtyping of group-specific component and protease inhibitor by rapid isoelectric focusing on PhastSystem

A rapid method on PhastSystem was used to investigate the distribution of group-specific component (GC) and protease inhibitor (PI) subtypes and their gene frequencies from 190 unrelated healthy donors of the Han population in Beijing. Laboratory-made gels (pH 4.5-5.4 and pH 4.2-4.9) were used for analysis of GC and PI, respectively. Sample loading was 1.5 mu L. The separation and visualization time was 0.5 h in each. Gene frequencies were as follows: GC*1F=0.4891, GC*1S=0.2432, GC*2=0.2678; rare GC variants were discovered in seven cases. The results for PI were: PI*M1=0.7542, PI*M2=0.1808, PI*M3=0.0650. Good agreement between the observed and expected values in both GC and PI subtyping (for GC, Sigma chi(2)=1.4043, 0.7<P<0.8; for PI, Sigma chi(2)=1.1233, 0.7<P<0.8) was obtained.