attract large amounts

Their high negative charge causes them to attract large amounts of cations over all the Na + which, due to its osmotic capacity, makes large amounts of water are retained in the extracellular matrix, keeping it hydrated producing a turgor pressure that enables the matrix to oppose compression forces.

The proteoglycans are the fundamental component of the animal extracellular matrix, constitute, so to speak, the main substance that fills the spaces that exist between the cells of the organism. They are also involved in the binding of water and cations such as sodium, potassium and calcium, as well as regulating the movement of molecules within the matrix. See More at https://foodsocietyx.com/nulante/