ISSN:
1573-5036
Keywords:
caffeate
;
citrate
;
Fe-mobilization
;
ferritin
;
Ferrozine
;
oxalate
;
phosphate
;
photoreduction
;
ultraviolet radiation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The release of Fe from horse spleen ferritin through photochemical reduction of Fe3+ to Fe2+ was studied in vitro. Spectrophotometric measurement of the Fe(Ferrozine)3 4− complex (specific for Fe2+) was used to quantify rates of Fe2+ mobilization. Light radiation from cool white fluorescent plus incandescent bulbs effectively promoted the rate of Fe2+ release. Compounds known to be present in plants provided further regulation of photorelease. Reductive removal from ferritin was inhibited by phosphate, and hydroxide, whereas citrate, oxalate, tartrate, and caffeate enhanced the release. Of the organic acids studied, caffeate was the only compound which induced detectable Fe2+ mobilization in the absence of irradiation. Rate constants for photorelease ranged from 2.7×10−3 sec−1 (pH=4.6) to 2.1×10−3 sec−1 (pH=7.1) at 26.5°C. These findings provide one possible explanation for the low level of ferritin-Fe in healthy, illuminated plant tissue.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00011857
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