Identification and purification of apolipoprotein C-III from the serum of cows.
OBJECTIVE
To identify, purify, and analyze distribution of apolipoprotein C-III in lipoprotein fractions and to evaluate its concentration in serum from calves, heifers, and cows during various stages of lactation.


METHODS
Sera from 3 female calves, 3 heifers, and 12 cows during early, middle, late, and nonlactation stages.


METHODS
Apolipoprotein C-III was identified by use of amino-terminal amino acid sequence analysis of bands separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purification was performed by extraction with acetone, delipidation with 2-propanol, and 2 chromatographic steps. The apolipoprotein C-III concentration in the total lipoprotein fraction was evaluated by densitometric scanning of the bands for apolipoprotein C-III separated by electrophoresis, using purified apolipoprotein C-III as an internal standard.


RESULTS
Apolipoprotein C-III was identified as 8.2- and 7.3-kd proteins with identical amino acid sequences. The 2 proteins were mainly found in the high-density lipoprotein fraction, then were purified separately. Serum apolipoprotein C-III concentration was significantly (P < 0.05) higher in cows during lactation than in nonlactating cows and was negatively correlated with serum triglyceride concentration (r = -0.620, P < 0.01).


CONCLUSIONS
The role of apolipoprotein C-III in cows may involve a function related to lactation.
Yamamoto
M
M
Fukushima Kenchu Livestock Hygiene Service Center, Japan.
Katoh
N
N
Adachi
Y
Y
Oikawa
S
S
D000375:Aging / Q000097:blood; D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000818:Animals; D053305:Apolipoprotein C-III; D001056:Apolipoproteins C / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007774:Lactation / Q000097:blood*; D008074:Lipoproteins / Q000097:blood / Q000302:isolation & purification; D010446:Peptide Fragments / Q000737:chemistry
D053305:Apolipoprotein C-III; D001056:Apolipoproteins C; D008074:Lipoproteins; D010446:Peptide Fragments