APOB

APOB Full Name

apolipoprotein B

APOB Introduction

Apolipoprotein B (APOB) is a large and essential lipoprotein structural protein encoded by the APOB gene, with two primary isoforms, ApoB100 and ApoB48, produced in the liver and intestine respectively. It serves as the major scaffold for atherogenic lipoproteins including very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and lipoprotein(a). Each of these particles carries exactly one molecule of apoB, making APOB not just a structural component but also a direct indicator of the number of circulating atherogenic particles in blood. APOB thus plays dual roles: stabilizing lipoprotein structure and mediating interactions with cell surface receptors like the LDL receptor, which enable lipid delivery to peripheral tissues throughout the body. This structural and functional significance underpins why immunoassays such as ELISA or Western blot use anti-APOB antibodies to study or quantify this protein in research and clinical settings.

Figure 1.The biosynthesis and physiological functions of apolipoprotein B (ApoB), and its relationship to cardiovascular diseases.

Functionally, apoB is central to lipid transport and metabolism, acting as the backbone of lipoprotein particles that carry cholesterol, triglycerides, and other lipids through the bloodstream. ApoB100 on VLDL and LDL is critical for assembly and secretion of these particles from the liver and for binding to LDL receptors, whereas ApoB48 is indispensable for chylomicron production in the intestine and dietary lipid absorption. Because there is one APOB protein per atherogenic particle, total plasma APOB levels provide a more precise measure of atherogenic burden than traditional cholesterol metrics like LDL-C, especially in conditions where particle number and cholesterol content diverge. This measurement precision has made APOB an increasingly important biomarker in cardiovascular risk assessment and therapeutic monitoring.

Clinically, elevated APOB is strongly linked to atherosclerosis and cardiometabolic disease. High levels of apoB-containing lipoproteins drive plaque formation in arterial walls, contributing to coronary heart disease, stroke, and broader atherosclerotic cardiovascular disease. Genetic mutations in APOB can lead to disorders such as familial defective apoB-100 or hypobetalipoproteinemia, which alter apoB function, lipid levels, and disease risk. Epidemiological and Mendelian randomization studies also show that higher genetically determined apoB shortens lifespan and increases risks of heart disease, stroke, and even type 2 diabetes, highlighting its importance both as a disease marker and a potential therapeutic target.

Alternate Names for APOB

APOB; apolipoprotein B; FLDB; LDLCQ4; apolipoprotein B-100; apoB-48; apoB-100; apo B-100; mutant Apo B 100; apolipoprotein B48; apolipoprotein B (including Ag(x) antigen);

• 1. Sniderman AD, et al.; Apolipoprotein B Particles and Cardiovascular Disease: A Narrative Review. JAMA Cardiol. 2019, 4(12):1287-1295.
  2. Borén J, et al.; Apolipoprotein B-containing lipoproteins in atherogenesis. Nat Rev Cardiol. 2025, 22(6):399-413.