Functional Proteins Isolated from Seaweeds

Several functional proteins are identified and extracted from seaweeds. Red seaweeds contain a higher amount of proteins compared to green and brown seaweeds. Based on the structure, functional proteins in seaweeds can be categorized as glycoproteins and lectins, phycobiliproteins, mycosporine-like amino acids, and peptides and hydrolysates. Glycoproteins are oligosaccharides (glycans) bound to the proteins with N-glycosylation or O-glycosyl linkages. Lectins are also a type of glycoprotein with a carbohydrate-binding domain that binds to specific sugar residues. Phycobiliproteins (PBP) are water-soluble fluorescent pigments mostly found in red seaweeds. There are several types of phycobiliproteins, such as phycoerythrin, phycocyanin, phycoerythrocyanins, and allophycocyanin. Mycosporine-like amino acids (MAA) are secondary metabolites produced by marine organisms, including seaweeds. Peptides and hydrolysates are produced by gastrointestinal digestion or hydrolyzation processes. Several studies suggested that seaweed functional proteins exert unique health benefits, including antioxidant, anti-obesity, antimicrobial and antihypertensive activities. In this chapter, we will briefly describe the bioactive properties of proteins isolated from seaweeds.