 So protein drugs that sounds like an awesome innovation. Why aren't all drugs protein drugs? Well, there are a couple of advantages and drawbacks here The on the plus side here We mainly had the specificity This specificity It's a bit unfair to only have one line for that But this specificity means that I can get this to target almost anything I want I have much more freedom if I want to make this hydrophobic or hydrophilic All the rules in the book that we've talked about for protein folding, you know the diversity right? I can do almost anything here and proteins are in general great at packing to other proteins So in addition to specificity, I can say efficient binding Although those are really part of the same property On the minus side on the other hand What do I have here? Sorry, there's one more part here. There are few side effects Why? Well, if I only bind to the right targets, right? I'm not going to have a whole lot of off-site binding and if there is no off-target binding, I won't have side effects On the minus sign the problem is that it is broken down And it's not just broken down in general This is broken down in your stomach by the proteases Meaning that we need injection Now if this is a life-saving cancer drug, I bet you won't mind getting an injection now and then But if it's a headache drug, you probably don't want to have an injection every time you have a headache, right? Unfortunately, there is another part of that too. This also clears fast What do we mean by clearing? Well, clearing is that when the body is getting rid of this We're pushing it through the liver or our kidneys and it goes out in the bathroom This is in general good for proteins and everything our body is designed to do that But for a drug you want a slow and steady release of a drug and if this is clearing fast You're now going to need maybe an injection three times a day. That's even less fun Again, if it's a cancer drug, you will do it But if you're a pharma company, you're looking for a drug that you can sell a lot and pharma companies hate drugs that have to be injected It's a almost a deal breaker Are there ways we could get around? Well, yes, there might be. Remember in the early lectures of this classroom when we spoke about properties of amino acids And there are particularly two parts that are intriguing here One of them is the D versus L amino acids and I mentioned biocompatibility So there's all our amino acids Including the proteases that are responsible for breaking things down our L amino acids Designing things with D amino acids might help us do something that is bio orthogonal And then it's not going to be broken down as quickly and maybe not clear as quickly That would be awesome Another possibility is to use artificial amino acids artificial meaning not one of the 20 natural ones that our body is used to use That too might enable you to have a protein that isn't quite as compatible But this dude, this is a very active development There are a whole lot of companies buying new companies that are specializing and so Biologicals is the collection name for all these drugs that are really biological compounds in particular peptides and proteins