Table 1. ß-glucosidase activity in coleoptile extracts of selected maize lines and hybrids.
Figure 1. a. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE, 12%T, 4%C) profiles of coleoptile extracts (soluble protein). b. Immunoblot of a developed with antiserum (R681) to ß-glucosidase. c. SDS-PAGE profiles of coleoptile pellet extracts (insoluble protein, extracted with SDS-sample buffer). d. Immunoblot of c developed with antiserum (R681) to ß-glucosidase. In both gels and blots, the cathode is at top. 1, F6; 2, CG10; 3, OH51A; 4, CO125; 5, CH586-12; 6, CH592-46; 7, CH593-32; 8, CH701-30; 9, MICH77-6; 10, CI.90A; 11, OH7B; 12, OH7BxH95; 13, H95; 14, H99xH95; 15, H99. Note the presence of an immunoreactive 60 kD polypeptide (ß-glucosidase monomer) in both null and normal genotypes and its increased amount in the insoluble fraction from null genotypes.
Western blots by immunostaining (Figs.
1b and 1d). Moreover, six out of seven null genotypes had a larger amount
of their 60 kD polypeptide in the insoluble fraction (Fig. 1d) than in
the soluble fraction (Fig. 1b). These data show that both the null and
the normal genotypes have similar amounts of the enzyme protein, but the
enzyme occurs mostly as insoluble or poorly soluble polymers in nulls and
does not enter the gel; thus, it is not detected by zymogram techniques.
The monogenic inheritance reported for the null alleles of the Glu
locus is likely to be for a factor encoded by another locus which affects
directly or indirectly the solubility of the enzyme by increasing its polymerization
into large quaternary structures.
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