Abstract

1 Abstract
Phosphatidylserine is well known protein .It is main function is in regard with memory and in brain cells. However it presence on the surface of the platelets as well. In this experiment , as a basic understanding , we are looking for to find a logic relationship between activation/inhibition of the platelets and manifesting phosphatidylserine .The hypothesis in this regard could be either no relationship or in case of relationship either increase or decreasing the amount of phosphatidylserine on the surface of the proteins. In a nutshell, in this experiment we will be involved with two processes. One is that first we activate the platelets by Thrombin and next time separately by ADP then we measure the amount of phosphatidylserine on the surface of the platelets. In second scenario we need to inhibit the platelets by Aspirin and then measure the phosphatidylserine. The measurement is performed by flowcytometry.
The problem was finding a way to measure the appeared molecules on the surface of the platelet. Annexin (a cellular protein with unknown functions up to now) has a property which is useful for this matter. Annexin family has over 160 members which share on a characteristic .They all share the property of Ca 2+ dependent binding to negatively charged phospholipid surfaces. The molecule which is preferred for this experiment is Annexin V. The mechanism of process is that Annexin V will be labelled with fluorescent materials. As it tends to bind to phospholipids on the surface of the platelet, hence it can bind to phosphatidylserine. Then by measuring the amount of Annexin V on surface of the platelets, indirectly we know the amount of phosphatidylserine on the surface of the platelet. As stated above the hypothesis is, expect for lack relationship scenario, activation the platelets by Thrombin/ADP could increase or decrease the externalisation of phosphatidylserine on the surface of the platelets .The second hypothesis could be: inhibition the platelets by Aspirin could increase or decrease the externalisation of phosphatidylserine on the surface of the platelets. In this experiment, plasma is taken from the blood of donors looks healthy and has not used Aspirin for at least a week ago. The findings could be used to have a basic understanding of their relationship which might be helpful in terms of producing a drug to suppress or stimulate this process.

Key Words: Annexin V, Phosphatidylserine, Flowcytometry, ADP, Thrombin, Aspirin, Externalization