In:
Zeitschrift für Naturforschung C, Walter de Gruyter GmbH, Vol. 30, No. 9-10 ( 1975-10-1), p. 634-637
Abstract:
The enhancement of CO 2 fixation in isolated, intact spinach chloroplasts by ascorbate or by low sulfite concentrations ( 〈 1 mм) is strongly reduced or even abolished by the addition of superoxide dismutase (SOD). By the use of 35 SO 3 2- it is demonstrated that the rate of sulfate formation is much lower than the sulfite induced increase in CO 2 fixation. This indicates that the superoxide radical is the chain initiating event; and, in parallel to ascorbate (Elstner and Kramer, 1973), the HSO 3 radical, acting as a Hill reagent for photosystem I, is reduced to sulfite in turn. The inhibitory action of sulfite at concentrations 〉 1 mм is not relieved by SOD, since this effect is mainly based on a competitive inhibition of ribulosediphosphate carboxylase. SOD itself stimulates the CO 2 fixation, if the reaction is started after 3 min of pre-illumination. This effect is discussed with respect to factors linked with the isolation procedure.
Type of Medium:
Online Resource
ISSN:
1865-7125
,
0939-5075
DOI:
10.1515/znc-1975-9-1013
Language:
English
Publisher:
Walter de Gruyter GmbH
Publication Date:
1975
detail.hit.zdb_id:
2078107-6
SSG:
12
Bookmarklink