The measurement of apolipoprotein A-I in human plasma by electroimmunoassay.
A variable proportion of the total apolipoprotein A-I (apo A-I) present in plasma or high density lipoproteins (HDL) is normally detectable by immunochemical methods. This has been attributed to masking of some of the immunoreactive sites of apo A-I by lipid in the intact HDL particle. This difficulty has been circumvented by heating or delipidation. We find that exposure of plasma to concentrations of urea greater than about 7.0 M in the barbital buffer used to dilute plasma samples for estimation by electroimmunoassay enables the complete detection of Apo A-I, as judged by comparison with samples delipidated with tetramethylurea. The need for time-consuming heating or delipidation is avoided.
D000328:Adult; D000368:Aged; D016632:Apolipoprotein A-I; D001053:Apolipoproteins / Q000097:blood*; D004587:Electrophoresis, Agar Gel; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D008782:Methylurea Compounds; D008875:Middle Aged; D014508:Urea
D016632:Apolipoprotein A-I; D001053:Apolipoproteins; D008075:Lipoproteins, HDL; D008782:Methylurea Compounds; C004168:1,1,3,3-tetramethylurea; D014508:Urea