Physiology and pathophysiology of cell organelles

Abstract

Lysosomes are found in the cytoplasm of all eucaryotic cells except mature red blood cells. The matrix of the organelle is separated from the surrounding cytoplasm by a trilaminar unit membrane and contains a variety of acid hydrolytic enzymes. Morphologically primary (recently formed from the Golgi-complex) are distinguished from secondary lysosomes. The latter type is formed after fusion of a vacuole with a primary lysosome and is ultrastructurally extremely heterogeneous due to the large variety of substrates (macro­ molecules ) incorporated in the matrix of the organelle. The acid hydrolases of lysosomes are divided into the following five groups: phosphatases, nucleases, polysaccharide- and glycosaminoglycans (GAG)-liydrolases, proteases and lipases.