Rapid screening method for polymorphism of group A apolipoproteins

Area of Science:

• Biochemistry
• Molecular Biology
• Clinical Chemistry

Background:

• Apolipoproteins AI and AII (apo AI and apo AII) are key components of high-density lipoprotein (HDL).
• Investigating the polymorphism of apo AI and apo AII is crucial for understanding lipid metabolism and cardiovascular disease risk.
• Previous methods for analyzing apo AI and apo AII isoforms were time-consuming, often requiring ultracentrifugation.

Purpose of the Study:

• To develop and validate a rapid, simple method for investigating apolipoprotein AI and AII polymorphism in human plasma.
• To enable the identification of apo AI and apo AII isoforms without the need for prior HDL isolation.

Main Methods:

• Incubation of EDTA plasma with urea, dithiothreitol, and Nonidet P-40.
• Isoelectric focusing (IEF) on ultrathin pH 4-6 acrylamide gels.
• Verification of apolipoprotein identity using immunofixation and immunoblotting with monospecific antibodies.

Main Results:

• Apolipoprotein AI (apo AI) resolved into one major band (apo AI0) and four minor isoforms (apo AI+2, apo AI+1, apo AI-1, apo AI-2).
• Apolipoprotein AII (apo AII) resolved into one major isoprotein (apo AII0) and two minor isoforms (apo AII+1, apo AII-1).
• The entire procedure, from sample preparation to visualization, was completed in 5 hours, significantly faster than previous methods.

Conclusions:

• The developed isoelectric focusing method provides a fast and effective means to analyze apo AI and apo AII plasma polymorphism.
• This technique eliminates the requirement for ultracentrifugation to isolate HDL, simplifying the analysis of apo AI and apo AII variants.
• The method is suitable for routine clinical and research applications requiring rapid assessment of apolipoprotein isoforms.