COVALENT BINDING OF DOLICHYL PHOSPHATE TO PROTEINS IN RAT-LIVER

被引:26
|
作者
THELIN, A
LOW, P
CHOJNACKI, T
DALLNER, G
机构
[1] KAROLINSKA INST,HUDDINGE HOSP,CLIN RES CTR,DIV MED CELL & NEUROBIOL,S-10401 STOCKHOLM 60,SWEDEN
[2] POLISH ACAD SCI,INST BIOCHEM & BIOPHYS,WARSAW 42,POLAND
来源
EUROPEAN JOURNAL OF BIOCHEMISTRY | 1991年 / 195卷 / 03期
关键词
D O I
10.1111/j.1432-1033.1991.tb15763.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Rats were injected via the portal vein with (RS)-[5-H-3]-mevalonolactone and the lipids were extracted. From fractions of liver homogenate, all labeled dolichol, cholesterol and ubiquinone could be extracted, but about 40% of microsomal and lysosomal dolichyl phosphate was only released after alkaline hydrolysis. Only a small amount of the non-extractable radioactivity was found to be associated with alpha-unsaturated polyprenyl phosphate. There was no difference in the polyisoprenoid pattern when the two pools of dolichyl phosphate were compared. On the other hand, the specific activity of the bound lipid was only half that of the extractable form. After phenyl-Sepharose chromatography, a peak of protein was isolated exhibiting a 25-fold enrichment in bound radioactive dolichyl phosphate. Treatment with a non-specific protease, followed by chromatography, gave polypeptide fragments associated with bound lipids. On SDS/PAGE a major protein band at 23 kDa and some minor bands with higher molecular masses were found to be associated with this lipid. The results indicate the presence of covalently bound dolichyl pholphate in rat liver.
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页码:755 / 761
页数:7
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