Relationship between hydrodynamic forces and vascular wall phenomena - II. Study of the influence of friction on the parietal microenvironment by the fixed enzyme method

Abstract

The study described is intended to demonstrate the relation which can exist in the parietal microenvironment between blood flow and metabolic surface phenomena. For this purpose modelisation technique is used. An enzymatic protein (beta galactosidase EC-3.2.1.23) is fixed on the internal surface of a nylon tube, throught which a calibrated flow of substrate (orthonitrophenyl β-D galactoside (ON PG) is generated by a pump. Variations in catalytic activity under influence of flow is monitored by enzymatic kinetic measurement. The influence of wall stresses G_M induced by continuous flow of substrate is studied. Distinction should be made between Michaelis behavioural reaction rate and reaction rate controlled by diffusion; for G_M values less than 125 s⁻¹, the process of substrate transfer to the wall depending on diffusion.