Lymphedema (lymphoedema in British English), also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstream.ymphedema (lymphoedema in British English), also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstream.
1 A polypeptide is a single linear chain of many amino acids, held together by amide bonds. 2  A protein is one or more polypeptide (more than about 50 amino acids long).  An oligopeptide consists of only a few amino acids (between two and twenty).
Of some of the polypeptides (proteins) some are enzymes. Enzymes catalyse reactions. Their poltpeptide shape--tertiary structure enables them to do this, as they have an active site which binds to the substrate.