Escaping parenthesis in regular expressions....

How does one escape parenthesis in a regular expression in Postgres?

An example is:

select * from subcategories where subcategory ~* '401(k)';

Which does not work. I've tried:

select * from subcategories where subcategory ~* '401\(k\)';

That still didn't work. Any advice would be much appreciated. BTW,

select * from subcategories where subcategory = '401(k)';

does work. ; )

steve