There are very few enclosed suites with personal doors and even fewer of them are assigned to a Business Class seat – usually those are marked as First Class. Here is the list of Business Class Suites:
There is another cabin not listed here – Malaysia Airlines Business Suites. Even though they were renamed from “first” to “business” recently, the price for those seats (money or award) is higher than regular business class seat on this airline, so it’s not a real business seat.