Pepsinogen 3, Group I (PGA3)

PGA3 belongs to the peptidase A1 family. Korsnes and Gedde-Dahl (1980) concluded that the pepsinogen I group must be coded for by more than one gene locus. They termed one locus PG5. The gene products differ from each other in the pepsin-coding part of the gene. The PG2, PG3 and weak PG4 electrophoretic bands are not coded for by alleles at the PG5 locus. They differ in the oligopeptides split off in pepsinogen-pepsin conversion. Bebelman et al. (1989) reported RFLP studies relating haplotypes to isozymogen patterns through a correlation of polymorphism at the DNA and protein levels. The findings supported the view that the isozymogen patterns are encoded by allelic haplotypes, encompassing different numbers and types of PGA genes. Exceptions suggested that rare haplotypes evolved by unique crossover events.