First of all, Alex, that was funny as hell…Did you really have to walk home. I can just picture it. I wouldnt even have been mad cause at least I got a good story out of it!
As far as digestive enzymes helping build muscle via more absorption. I dont think so unless you are deficient and your absorption is very poor. Most bodybuilders (myself included) take in way above their needs of protein. I do it just to be safe so that I have enough protein around when I need it. Also, I like to eat it and it is a nice way to stay lean on higher calorie diets. So I dont think any of us (at 1g/lb or above) are limited in muscle building potential by the absorption of our protein.
About the questions though, typically the body can handle protein pretty well. But this all goes out the window when you're eating alot like many bodybuilders do (I eat 400-450g per day). I find that the gas is not always due to the protein itself. It may be the protein plus all the food taxing the digestive tract. Also, you may be consuming lactose and be sensitive to that. I never was lactose intolerant until I was 20 or so. Now, it could have just developed over time but I believe that my super high milk consumption in my teen years and my huge caloric intake contributed to it. And this belief is not just based on my story. I have at least 5 friends that never started experiencing lactose intolerance till they started bodybuilding and eating like a bodybuilder. So that is where you can first start in terms of eliminating gas. Use lactaid milk.
Next, digestive enzymes like Bromelain may help digest the protein on high intakes, which may lead to less waste and less gas. Theoretically then you wouldnt have to eat as much protein. I wouldnt do that, though, as you can never be sure that the enzyme is actually helping digestion and absorption of protein. One concern is that often the enzymes may be broken down before they can work. But I know alot fewer guys have to walk home when taking these enzymes. They can only help and arent that expensive so it cant hurt to try it out.
About the liver, it doesnt produce the enzymes for protein metabolism. Precursors of the active digestive enzymes trypsin chymotrypsin and pepsin are released from the pancreas and are converted in the stomach or intestine to active enzymes. Here they are free to break up protein bonds into peptides and aminos. The ability of the pancreas to release these enzymes is good and it doesnt get stressed.