Interaction of Myoglobin Model with Ligands of Gas Exchange

Abstract

Introduction. Gas exchange for living organisms is a very important biochemical process. Hemoglobin blood – imioglobin plays a leading role in him, located in the muscle fibers. In the study of various indicators of the cardiovascular and respiratory systems, the question arose about the competition of different gases for binding to Fe 2+ h a em h a emoglobin. Purpose. Until this time, nobody considered the possibility of binding of СО 2 to iron of haemoglobin. For the first time, we have taken an attempt to consider this connection. Methods. Calculations were made using ZINDO / 1 and PM3 methods in the HyperChem program. Results . The issue of gas exchange with participation of haemoglobin is discussed. The potential curves of haem iron binding with CO, СО 2 and О 2 gases are calculated. The possibility of forming a complex for the haem model with carbon (IV) oxide is shown for the first time. The role of the upper occupied MO of iron-phosphorus and ligand in the formation of coordination bonds and charge transfer in the complex of haem with СО 2 is determined. The role of charge polarization in the haem model is considered comparing СО 2 with other gases. Conclusion . Our quantum-chemical calculations show that СО 2 can be coordinated with the iron ion in haemoglobin, although its binding energy is significantly less than that for the CO complex with haemoglobin and is about 34.5 kcal / mol.