...
while( $stuff =~ /^ (\d+): \s+            # the number xx: => $1
                    (\w+)  \s+            # the locus => $2
                    ( (?:.(?!^\d+:))+ )   # the remaining record => $3
                 /msgx ) {
   my ($locus, $name, $record, $kegg, $func, $proc, $comp) = ($2, '', $3, ('unknown')x4);
   $name = $1 if $record =~ /([^\n\[]+)\s*/;
   $kegg = $1 if $record =~ /KEGG \s+ pathway: \s+ (.+?)\s+Function \s+ Evidence/sx;
   $func = $1 if $record =~ /Function  \s+ Evidence \s+ (.+?) (?:\n\n|\z)/sx;
   $proc = $1 if $record =~ /Process   \s+ Evidence \s+ (.+?) (?:\n\n|\z)/sx;
   $comp = $1 if $record =~ /Component \s+ Evidence \s+ (.+?) (?:\n\n|\z)/sx;
   print join "\n\n", $locus, $name, $kegg, $func, $proc, $comp;
}
...