Plasma and tissue proteins

Plasma and tissue proteins refers to the diverse set of proteins found in the blood and interstitial spaces, including albumin, globulins, and various structural proteins (StatPearls, 2023). This term is considered an incorrect or overly broad designation for a therapeutic target because it represents a physiological compartment or a collection of thousands of distinct molecules rather than a specific, druggable entity like a single receptor or enzyme (NCBI, 2022). In pharmacology, these proteins are primarily relevant for their role in drug-protein binding, which significantly influences the pharmacokinetics, distribution, and free concentration of drugs in the body (DrugBank Online, 2024). For example, albumin is the major carrier for acidic drugs such as warfarin, while alpha-1-acid glycoprotein binds basic drugs like propranolol (PubMed, 2021). Variations in the levels of these proteins due to conditions like liver cirrhosis or renal failure can lead to unpredictable drug effects and increased risk of toxicity (Merck Manual, 2023). Consequently, while these proteins are essential to understanding drug behavior, the collective term is too non-specific for use as a precise molecular target.

Other names

Serum proteinsCirculating proteinsExtracellular proteinsPlasma protein binding sitesBlood proteins

Non-specific binding to plasma and tissue proteins, primarily albumin and alpha-1-acid glycoprotein, which sequesters the drug in the vascular or extravascular space and regulates the pharmacologically active free fraction.