Kinetic and spectroscopic studies of cytochrome b-563 in isolated cytochrome b/f complex and in thylakoid membranes Page: 4 of 11
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
1 2 3
37k — * *
f tet ,*«* oo
JM jf.. V
6 M tM •»«*►«**
17k «— —
#* *
Figure 1. Effect of alkalai
bromides on the 37 kD
polypeptide. Lanes 1 and 2:
40—60% saturation ammonium
sulfate precipitates of octyl
glucoside/ cholate extracts
from thylakoids washed twice
with 2 M NaBr (Lane 1) or with
5 mM EDTA (Lane 2). Lane 3:
Isolated b/f complex (Clark,
Hind 1983). Lane 4: 40%
saturation ammonium sulfate
precipitate of isolated b/f
complex after incubation with 2
M LiBr. Lane 5: b/f complex
purified according to Hurt and
Hauska (1982).
Use of fresh leaf material and inclusion of PMSF leads to a product
with only one heme-staining band near the 34 kD band (cyt f) on SDS-
polyacrylamide gels. Our alternative protocol also conserves a non-heme
polypeptide running at 37 kD. This band comigrates with the complex on
sucrose gradients (Clark, Hind 1983). Fig. 1 shows that the 37 kD
component is removed from the complex in situ and after isolation, upon
treatment with 2 M bromide accounting for its absence from the
preparation of Hurt and Hauska. The functioning of this component is
not yet known, but is under intensive study. Complex isolated by either
of the above procedures is about equally active in the PQH-J plastocyanin
oxidoreductase reaction.
As described elsewhere (Clark, Hind 1983), our five-polypeptide
complex contains the two distinct cyt _b-563 hemes also present in the
• V tQ. .v I
control +HQN0 +HQN0, +Fd
asc
Figure 7. Effects nf HQNO
and ferredoxin reduction on the
cyt _b-563 spectrum in the _b/f_
complex at 77°K. Control:
spectrum of sample frozen TOs
after dithionite addition.
HQNO: inclusion of 40 pM HQNO,
0.5% ethanol before dithionite
addition. Asc: 1 mM ascorbate
included j.u Llie incubation
prior to reduction with
dithionite. Fd—: complex
reduced with ferredoxin for 15
min before freezing. Samples
contained 3 pM b/f in 20%
glycerol, 0.5% cholate, 20 mM
NaTricine (pH 7.5). The
optical pathlength was 2 mm.
The arrows indicate 560 nm.
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Hind, G.; Clark, R.D. & Houchins, J.P. Kinetic and spectroscopic studies of cytochrome b-563 in isolated cytochrome b/f complex and in thylakoid membranes, article, January 1, 1983; Upton, New York. (https://digital.library.unt.edu/ark:/67531/metadc1103069/m1/4/: accessed March 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.