Fibrinogen

This is a β-glycoprotein composed of 2700 amino acids. The length of the fibrinogen molecule is about 46 nm, the molecular mass is 330,000-340,000 Da, in electrophoretic field it is between β and γ globulins. Synthesized in the human liver. In human blood plasma, it is present at 8.2-12.1 mmol/l. Its molecule is composed of α, β, and γ chains. All 6 chains join in the center of the molecule forming the E region. The two lateral parts of the molecule are called D regions. There are two signaling amino acid sequences in the fibrinogen molecule: in the α chain – the RGD (Arg-Gly-Asp) sequence, and in the γ chain – the KQAGDV (Lys-Glu-Ala-Gly-Asp-Val) sequence. These amino acid sequences are recognized by fibrinogen platelet receptors. Then the fibrinogen molecule can bind to two receptors present on the membranes of different platelets. When the fibrinogen molecule binds to the GPIIb IIIa receptor, the initial seconds and minutes of the binding are reversible, later, as fibrinogen bridges form between these receptors, the binding becomes irreversible.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė