Typical formulation for Analogue Pizza Cheese, from Fundamentals of Cheese Science:

  Ingredient               Level added (g/100g Blend)
  Casein and caseinates    23.00 
  Vegetable oil            25.00   
  startch                  2.00    
  Emulsifying salts        2.00    
  Flavour                  2.00    
  Flavour enhancer         2.00    
  Acid regulator           0.40
  Color                    0.04
  Preservative             0.10
  Water                    38.50
  Condensate^              7.00

^ Upon cooking the blend to about 85°C using direct steam injection, condensate equivalent to about 7.0 g is absorbed by the blend.

There is a different but similar product, processed cheese, that is actually made with cheese and various additives to manipulate its taste, texture, rheological characteristics etc. The difference with APC is that APC does not include cheese (but as the table above shows, it does include caseins).

[Note that the numbers above add to 102.04 so there may be a mistake, or the numbers are only estimates. Also note I have an old edition of the book. Numbers and ingredients may well have changed more recently.]