ISSN:
1573-6881
Keywords:
Ubiquinol-cytochrome c reductase
;
core proteins
;
topology
;
proteolysis
;
immunoreplica
;
Complex III
;
respiratory chain (bovine heart mitochondria)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract The topology of beef heart Complex III has been studied by tryptic and chymotryptic digestion of isolated Complex III, Mg2+-ATP submitochondrial particles, and mitoplasts. Degradation products were detected by the immunoreplica technique using specific antibodies against core protein 1 (50 K) and core protein 2 (47 K). It can be shown that both peptides are digested from the matrix side of the inner membrane. However, no evidence was found that these peptides were digested by trypsin or chymotrypsin from the cytoplasmic side. It is concluded that the beef heart core proteins are membrane-bound peptides containing tryptic and chymotryptic digestion sites only on the matrix surface of the inner membrane. The data also suggest that beef heart core protein 2 contains multiple domains which are inserted into the membrane from the matrix surface. Proteolytic treatment of submitochondrial particles under conditions which digested at least 50% of the core proteins from the matrix surface did not, however, influence NADH oxidation rates or the respiratory control ratios.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00743485
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