Читать книгу Cell Biology - Stephen R. Bolsover - Страница 46

Lysosomes vary in shape and size but are often spherical, with a diameter of 250–500 nm. They are particularly plentiful in cells that digest and destroy other cells, such as the white blood cells called macrophages. This relates to their primary function in degrading material. Indeed, lysosomes are sometimes called “cell stomachs” because they contain a battery of enzymes that digest cellular components. Over 50 such enzymes exist, responsible for the breakdown of proteins, lipids, and even damaged organelles. Many of the enzymes show an acidic pH optimum, meaning that they function most efficiently at low pH. For this reason, lysosomes maintain a pH of 4–5. This aids breakdown of the material. We shall return to lysosomes in Chapter 12.