defined' );
$s1->fix(2.1);
ok( $var->value == 2.1, 'fix substrate concentration' );
$s1->release;
isnt( defined $var->value(), 'release substrate concentration' );
# Reaction
my $r1 = Bio::Metabolic
ned' );
#$s1->fix(2.1);
#ok( $var->value == 2.1, 'fix substrate concentration' );
#$s1->release;
#isnt( defined $var->value(), 'release substrate concentration' );
my $s3 = Bio::Metabolic::Substrate-