In Silico Analysis of Relationship between Proteins from Plastid Genome of Red Alga Palmaria sp. (Japan) and Angiotensin I Converting Enzyme Inhibitory Peptides

Plastid proteins are one of the main components in red algae. In order to clarify the angiotensin I converting enzyme (ACE) inhibitory peptides from red alga Palmaria sp. (Japan), we determined the plastid genome sequence. The genome possesses 205 protein coding genes, which were classified as genetic systems, ribosomal proteins, photosystems, adenosine triphosphate (ATP) synthesis, metabolism, transport, or unknown. After comparing ACE inhibitory peptides between protein sequences and a database, photosystems (177 ACE inhibitory peptides) were found to be the major source of ACE inhibitory peptides (total of 751). Photosystems consist of phycobilisomes, photosystem I, photosystem II, cytochrome complex, and a redox system. Among them, photosystem I (53) and II (51) were the major source of ACE inhibitory peptides. We found that the amino acid sequence of apcE (14) in phycobilisomes, psaA (18) and psaB (13) in photosystem I, and psbB (11) and psbC (10) in photosystem II covered a majority of bioactive peptide sequences. These results are useful for evaluating the bioactive peptides from red algae.