A novel antiserum specific to apolipoprotein B-48: application in the investigation of postprandial lipidaemia in humans.
1. Apolipoprotein B-48, the transport protein for chylomicrons, is identical with apolipoprotein B-100 for the first 48% of its sequence. No antiserum has yet been reported that can recognize apolipoprotein B-48, but not apolipoprotein B-100. 2. In the present study an antiserum was raised to the C-terminal sequence of apolipoprotein B-48, using specific chemical reactions to ensure that the charged carboxyl group of the C-terminal isoleucine residue was free. In a Western blot the antiserum was shown to bind to a protein band having the characteristics of apolipoprotein B-48, but not to apolipoprotein B-100. 3. In the early evening 11 subjects were given a test meal which contained 40 g of mixed oil and retinyl palmitate. Blood samples were collected over 9 h. Chylomicron-enriched fractions were prepared and analysed for triacylglycerol, retinyl palmitate and apolipoprotein B-48, the latter after separation using SDS/PAGE and visualization by chemiluminescence on a Western blot. Both triacylglycerol and apolipoprotein B-48 showed an early peak at 1 h, which was not seen with retinyl palmitate. All three substances gave a broader peak between 5 and 6 h postprandially. Retinyl palmitate concentrations declined rapidly during the late (6-9 h) postprandial period, but apolipoprotein B-48 concentrations remained elevated. 4. This study has shown that an antiserum has been produced which is specific for apolipoprotein B-48. This has enabled measurement of postprandial concentrations of the protein that revealed features of chylomicron metabolism which have not been reported previously.
Peel
A S
AS
Nutritional Metabolism Research Group, School of Biological Sciences, University of Surrey, Guildford, U.K.
Zampelas
A
A
Williams
C M
CM
Gould
B J
BJ
D000328:Adult; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000032:analysis* / Q000378:metabolism; D015153:Blotting, Western; D002914:Chylomicrons / Q000378:metabolism; D004224:Diterpenes; D004435:Eating / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007106:Immune Sera; D008055:Lipids / Q000097:blood*; D008297:Male; D009821:Oils / Q000378:metabolism; D012172:Retinaldehyde / Q000031:analogs & derivatives / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D002914:Chylomicrons; D004224:Diterpenes; D007106:Immune Sera; D008055:Lipids; D009821:Oils; D014280:Triglycerides; C033889:retinal palmitate; D012172:Retinaldehyde