Macromolecule Binding

Macromolecules are large molecules including carbohydrates, lipids, proteins, and nucleic acids. In this juncture, macromolecules refer to proteins such as albumin, globulin or lipoproteins. Biologics are transported through the lymphatic tissues into the vascular system, followed by distribution in the interstitium, and finally reaching the intracellular structure. Macromolecule binding may hinder the rate of distribution and transport, hence impeding the onset of pharmacological action. On the other hand, macromolecule may preserve the biologics from quick turnover and actually favor therapeutic effect. The manifestation of macromolecule binding is multifaceted and intriguing. So is the receptor binding, which not only leads to therapeutic response but also subsequent catalytic metabolism.

Macromolecule binding is largely non-specific, but there are bindings to specific proteins as well. Macromolecule binding may hinder the rate of distribution and transport, hence impeding the onset of action. On the other hand, macromolecule may preserve the biologics from quick turnover and actually favor therapeutic effect. Binding and complexation of growth hormone with plasma protein is an example. Receptor binding is specific by nature; it not only leads to pharmacological effect but could be followed by catalytic metabolism. In this regard, it is to be noted that limited uptake of Nartograstim is sufficient for target recognition because of high affinity. Several PK/PD aspects of macromolecule binding will be encapsulated.