I try to measure the enzyme concentration for the NO3 which is an endothelial enzyme expressed mainly in the endothelial tissues, some literature report measuring from blood samples, but is it a representative to the endothelial tissues?
Measuring of serum enzymes indicates damage of this tissue, neither intracellular expression nor activity, i give you some options for estimation endothelial enzymes: 1. estimation of enzymes activity from tissue after homogenize it. 2. At the molecular level by gene expression. 3. Estimation mass concentration of the protein (enzyme) by immunohistochemistry.
Thank you very much for your response your answer is really helpful. I agree with you serum samples for sure indicate damaging to the endothelium tissues. regarding the gene expression that you mention, what the type of sample that i will extract mRNA from it ? do you suggest cell culture or something else? please explain more.
First RNA will be extracted and they are many methods for gene expression for eg Microarrays or to use immunohistochemitry by specific monoclonal antibody to the enzyme in endothelial tissue section or immunocytochemistry of mono-layer of endothelial cells the result is mass concentration of enzyme.