use strict;
use Bio::SeqIO;
use Data::Dumper;
use Bio::Tools::pICalculator;
  
my $filename="c:\\uniprot_sprot.dat";
my $sequence_object;

my $seqio = Bio::SeqIO -> new   (
                                '-format' => 'swiss',
                                '-file' => $filename
            );

my $calc = Bio::Tools::pICalculator->new(-places => 2,
                                           -pKset => 'EMBOSS');

my $c;

while ($sequence_object = $seqio -> next_seq) {
$c++;
#my $sequentie = $sequence_object-> id(); 
#print Dumper $sequence_object;
$calc->seq($sequence_object);
     my $iep = $calc->iep;
     print sprintf( "%s\t%s\t%.2f\n",
                    $sequence_object->id,
                    $iep,
                    $calc->charge_at_pH($iep) );

last if $c >= 1000;
}