Wow, I've only read the abstract so far but this basically goes against all conventional research on this topic AFAIK. I read probably ~50 papers on this topic (maximal protein dosing) and emailed a few researchers about it as I was writing a book. I believe the saturation point for a relative dose for a single meal is generally held to be ~0.25g per kg of bodyweight. Of course, there are some obvious observable issues with this belief given that there are people who practice intermittent fasting and have no issues building muscle, so it'll be really interesting to see if this study replicates

EDIT: After skimming the paper, I don't see anything immediately wrong with it. But there are some important nuances to note: the subjects were all fasted and given milk protein (casein in milk protein is known to take longer to absorb than pure whey protein which is a popular choice for these studies), and the measurements were made after an hour of exercise. This would skew the results towards more protein sensitivity than in normal settings where a person is pretty much always somewhat well-fed and not always eating after exercise. This is still encouraging because the results for post-exercise protein metabolism have still indicated a much lower limit than a 100g dose. Their report that oxidation rates didn't increase significantly is also notable since the belief has generally been that excess protein is oxidized and burned for energy instead of being incorporated into muscle. However, it would've been nice for them to include a 50g group as well to see if the dose-response relationship was really still linear between 25-50-100

Ultimately, this result seems encouraging for increasing post-exercise protein consumption for muscle gain, but we shouldn't discount the fact that the subjects were fasted before exercise. It would be interesting to see this study prolonged over the course of a day with further protein ingestions to see if the area-under-the-curve of muscle protein synthesis would eventually equalize in both groups, or if the larger immediately-post-exercise dose made a lasting difference. Existing research seems to not indicate such an "anabolic window". I might speculate that there is a daily limit for protein ingestion, but it doesn't matter if you hit that limit in one meal or five. That said, I have previously come across a paper that found medium-sized, spaced out doses to be more effective than infrequent large doses and overly frequent small doses, so there's still more to discover here