TABLE 5.

High Mg²⁺ concentrations inhibit three-factor-dependent conversion of 70S ribosomes into subunits^a

Mg2+ concentration Incubation with	70S converted into subunits (%)
14 mM Mg2+
a) -	-
b) IF3 (4.5 μM)	1.9
c) RRF (1 μM), EF-G (1 μM), GTP (0.36 mM), IF3 (4.5 μM)	15.9
20 mM Mg2+
a) -	-
b) IF3 (4.5 μM)	3.8
c) RRF (1 μM), EF-G (1 μM), GTP (0.36 mM), IF3 (4.5 μM)	3.2

^aConversion of w-ribosomes into subunits at 14 or 20 mM Mg²⁺ was examined as described in Table 1 except that buffer V (10 mM Tris-Cl, pH 7.4, 14 mM MgSO₄ , 80 mM NH₄Cl, 0.2 mM DTT) or buffer W (10 mM Tris-Cl, pH 7.4, 20 mM MgSO₄ , 80 mM NH₄Cl, 0.2 mM DTT) was used instead of conventional buffer R.