A fraction of highly purified prolamellar bodies was isolated from etioplasts of 
wheat (Triticum aestivum L. cv. Starke II, Weibull), as previously described by 
Ryberg and Sundqvist (1982, Physiol. Plant., 56, 125-132). Studies on the 
protein composition revealed that only one major polypeptide of an apparent 
molecular weight of 36000 is present in the fraction of prolamellar bodies. This 
polypeptide was identified as the NADPH-protochlorophyllide oxidoreductase. The 
highest specific activity of the enzyme in etiolated leaf tissue was confirmed 
to be in the fraction of prolamellar bodies.