Digestion of polymerase chain reaction products by restriction enzymes. (A) Arg to His genotype variation at codon 60 of LMP2. Lanes 1, 2 and 5, Arg/Arg homozygous cells, yielding bands of 250 and 79 bp; lanes 3 and 6, Arg/His heterozygous cells, yielding bands of 329, 250 and 79 bp; and lanes 4 and 7, His/His homozygous cells, yielding a band of 329 bp. (B) Glyn to Lys genotype variation at codon 145 of LMP7. Lanes 8, 10 and 11, Gln/Gln homozygous cells, yielding bands of 205 and 146 bp; lanes 9 and 13, Gln/Lys heterozygous cells, yielding bands of 351, 205 and 146 bp; and lanes 12 and 14, Lys/Lys homozygous cells, yielding a band of 351 bp. LMP, low molecular weight protein.