my %fasta_seen;

FASTA_RECORD:
while ( my $para = <$PROTFILE> ) {
  # Remove fasta header line
  if ( $para =~ s/^>(.*)//m ){
     $name = $1;
  };
  # Remove comment line(s)
  $para =~ s/^\s*#.*//mg;

  next FASTA_RECORD if $fasta_seen{ $para }++;

  …