Carbonic anhydrase 1 is an enzyme that in humans is encoded by the CA1 gene. Carbonic anhydrases are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide.
It is becoming more common that the latte macchiato will have a layer of milk foam on the top of the drink as well. A latte is steamed milk, espresso, and a 1/4 inch of foam ontop. It is prepared in this order: flavored syrup (if applicable), espresso, steamed milk, topped with 1/4 inch of foam.
For latte, the goal is not to create that much foam, so any type of milk works. For cappuccino, we start with equal portions of espresso and milk. The milk is then frothed (in a special frothing pitcher) into a microfoam that is roughly double the original volume of the milk. The microfoam is then poured over the espresso. (If the espresso is poured into the microfoam, then the drink is called a latte macchiato.)