Photoreceptor protein from the purple membrane of Halobacterium halobium. Molecular weight and retinal binding site

Biochemistry ◽  
1976 ◽  
Vol 15 (4) ◽  
pp. 792-798 ◽  
Author(s):  
John Bridgen ◽  
Ian D. Walker
FEBS Letters ◽  
1978 ◽  
Vol 91 (1) ◽  
pp. 131-134 ◽  
Author(s):  
David Cahen ◽  
Haim Garty ◽  
S.Roy Caplan

1988 ◽  
Vol 152 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
Yoshihiro Nakata ◽  
Chie Hiraoka ◽  
Tomio Segawa

1975 ◽  
Vol 53 (3) ◽  
pp. 364-370 ◽  
Author(s):  
J. A. Kornblatt ◽  
W. L. Chen ◽  
J. C. Hsia ◽  
G. R. Williams

Cytochrome oxidase, an enzyme containing six different subunits, has been shown to span the inner mitochrondrial membrane. The arrangement of the subunits within the membrane is unknown. We have specifically labeled the 25 000 molecular weight subunit with a spin-label derivative of N-ethylmaleimide, 3-maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (NEM-SL(5)). NEM-SL(5)-labeled cytochrome oxidase can be incorporated into phospholipid membranes to form coupled vesicles of the Hinkle, Kim &Racker ((1972) J. Biol. Chem. 247, 1338–1339) type. The resonance spectrum of NEM-SL(5) is similar in both soluble and vesicular cytochrome oxidase. Since ascorbate has been shown to reduce only spin label that is exposed to the exterior surface of a closed vesicle, we have used ascorbate to determine the NEM-SL(5)-binding site in the coupled vesicles. NEM-SL(5)-labeled cytochrome oxidase vesicles are reduced by 10 mM ascorbate with [Formula: see text] of 1 min at 22 °C. The rate of reduction is relatively independent of temperature. We conclude that (1) cytochrome oxidase is unidirectionally or preferentially oriented in the vesicle membrane, and (2) the NEM-SL(5)-binding site on the 25 000 molecular weight subunit is exposed to the external aqueous medium.


1998 ◽  
Vol 75 (2) ◽  
pp. 777-784 ◽  
Author(s):  
Leonardo Pardo ◽  
Francesc Sepulcre ◽  
Josep Cladera ◽  
Mireia Duñach ◽  
Amílcar Labarta ◽  
...  

1987 ◽  
Vol 6 (6) ◽  
pp. 451-458 ◽  
Author(s):  
W. Rau ◽  
F. Planas-Bohne ◽  
D.M. Taylor

1 Male Sprague-Dawley rats were injected with 109CdCl2 (3 μmol Cd/kg) and killed between 1 h and 200 d afterwards. Metal concentration in the critical organs, i.e. liver and kidneys decreased very slowly. Within the cells Cd is found mainly in the cytosol and — at very early times — in the nuclei. Within the cytosol of the liver most of the metal is initially bound to proteins with high molecular weight but as early as 3 h after incorporation more than 90% is bound to metallothionein which is always the main binding site in the kidneys. 2 Of the chelating agents tested only BAL and Puchel were able to reduce the body burden significantly. Both are lipophilic substances. Puchel cannot reduce the kidney Cd burden but removes Cd from the liver only while BAL is effective in both organs. Both chelating agents exert their effects at doses which are too near to the LDso to be considered as safe enough for human use.


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