my @fields = split /\t/, $tsv_line;

if ( $fields[0] eq 'SEQ' ) {
    print "Header of Predictions\n";
}
elsif ( join("", @fields[0,1]) =~ /^\w\w$/) {
    push @ProteinSeq, $fields[0];
    push @Prediction, $fields[1];
    printf "Amino acid is: %s and Prediction is: %s\n", @fields[0,1];
}