TABLE 1.
Molecular and catalytic properties of recombinant (3S)-malyl-CoA/β-methylmalyl-CoA lyase and (3S)-malyl-CoA thioesterase from R. sphaeroides
| Property | (3S)-Malyl-CoA/β-methylmalyl-CoA lyase (Mcl1) | (3S)-Malyl-CoA thioesterase (Mcl2) |
|---|---|---|
| Reaction(s) catalyzed | Acetyl-CoA + glyoxylate ⇆ (3S)-malyl-CoA Propionyl-CoA + glyoxylate ⇆ β-methylmalyl-CoA | (3S)-Malyl-CoA → (3S) malate + CoA |
| Sp act, U mg−1 (reaction) | 14 (condensation of acetyl-CoA + glyoxylate), 4.1 [cleavage of (3S)-malyl-CoA], 20 (condensation of propionyl-CoA + glyoxylate), 4.5 (cleavage of β-methylmalyl-CoA) | 200 (thioester cleavage) |
| Apparent Km value(s), mM (substrate) | 0.1 (acetyl-CoA), 3.1 (glyoxylate), 0.02 [(3S)-malyl-CoA], 0.2 (propionyl-CoA), 4.1 (glyoxylate), 0.01 (β-methylmalyl-CoA) | 0.09 [(3S)-malyl-CoA] |
| Turnover no. per subunit kcat, s−1 (reaction) | 8.6 (condensation of acetyl-CoA + glyoxylate), 2.5 [cleavage of (3S)-malyl-CoA], 12 (condensation of propionyl-CoA + glyoxylate), 2.8 (cleavage of β-methylmalyl-CoA) | 110 (thioester cleavage) |
| Catalytic efficiency per subunit kcat/Km, M−1 s−1 (reaction) | 2.8 × 103 (condensation of acetyl-CoA + glyoxylate), 1.3 × 105 [cleavage of (3S)-malyl-CoA], 3.0 × 103 (condensation of propionyl-CoA + glyoxylate), 2.8 × 105 (cleavage of β-methylmalyl-CoA) | 1.2 × 106 (thioester cleavage) |
| Influence (sp act, %) of cations/inhibitor at 10 mM each | Mn2+, 100; Mg2+, 73; Ca2+, 14; Co2+, 13; Ni2+, 6; EDTA, 1 | Mg2+, 100; Mn2+, 40; Ca2+, 19; Co2+, 3; Ni2+, 7; EDTA, 1 |
| Native molecular mass (kDa) | 200 | 80 |
| Subunit molecular mass (kDa) | 36.8 | 33.4 |
| Suggested composition | α6 | α2 or α3 |