theres no set number on how much protein can be obsorbed by the body in 1 sitting
While this may be technically true, protein needs to be broken down into amino acids for it to be of use. Protein is broken down by proteinases/proteases enzymes so when large sums of protein are ingested that require these enzymes a situation can arise where there is not ample enzyme available to break down the protein which means they can pass through the system without being properly broken down and in turn some of the nutrients wasted.