Water Proton Relaxation as a Monitor of Membrane-Bound Manganese in Spinach Chloroplasts.
Abstract
First measurements of proton relaxation on chloroplast membranes are presented here. Experiments show that the water proton spin-lattice relaxation rate in chloroplast thylakoid membrane suspensions can be used to monitor membrane-bound manganese. The relaxation effect is reduced to 0.4 of its original value upon manganese extraction by washing with either alkaline tris buffer of NH2OH-EDTA solution. Large increases in the proton relaxation rate are measured in the presence of reductants such as tetraphenylboron and NH2Oh; oxidants such as potassium ferricyanide or 2,6-dichlorophenolindophenol lead to a decrease in this rate. These results suggest that manganese exists as a mixture of oxidation states in dark-adapted chloroplasts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 03, 1975
- Accession Number
- ADA016646
Entities
People
- Govindjee
- N. Zumbulyadis
- P. G. Schmidt
- T. Wydrzynski
Organizations
- University of Illinois Urbana–Champaign