Nickel is not required for apourease synthesis in soybean seeds.
Soybeans (Glycine max L. Merr. cv ;Maple Presto') harvested from plants cultured in nickel-free medium had <0.005% the activity of nickel-sufficient beans and only 15% the activity of a urease-null variety, Itachi. However, whereas Itachi has no detectable urease protein, nickel-free beans of the variety Maple Presto exhibit normal or near normal levels of urease apoprotein. Thus, nickel isn't necessary for urease apoprotein synthesis. The apoprotein wasn't activated by nickel in vitro but, upon seed imbibition of nickel, urease was partially activated. This in vivo activation was not inhibited by cychoheximide.
Winkler
R G
RG
Department of Biochemistry, University of Missouri, Columbia, Missouri 65212.
Polacco
J C
JC
Eskew
D L
DL
Welch
R M
RM