Table 1. Specific activities of methanol dehydrogenase, of enzymes of the serine cycle and of the ethylmalonyl-CoA pathway in extracts of M. extorquens cells grown on methanol, acetate or succinate.
| Specific activity [nmol min−1(mg protein)−1]* | Requirement for growth on | |||
| Methanol | Acetate | Succinate | ||
| This work/previous work | This work/previous work | This work/previous work | ||
| Methanol dehydrogenase | 64±12/70 [25], 540 [26], 320 [27], 64 [28] | 9±0.7/n.d.# | <1/60 [26], 5 [27] | C1 |
| SERINE CYCLE | ||||
| Serine hydroxymethyl transferase | 24±7/30 [29], 42 [30], 60 [31] | 4±0.6/n.d. | 2±0.2/5 [29], 13 [30] | C1 |
| Serine-glyoxylate aminotransferase | 630±80/83 [26], 120 [27], 165 [28] | 52±11/n.d. | 45±5/0 [26], 15 [27] | C1 |
| Hydroxypyruvate reductase | 1,500±300/1,533 [26], 343 [28], 1,200 [29], 1,570 [30], 2,250 [32] | 400±86/n.d. | 600±10/266 [26], 330 [29], 350 [30] | C1 |
| Glycerate kinase | 130±3/52 [26], 36 [27], [33], 11 [28], 40 [34] | 27±6/n.d. | 23±3/16 [26], 14 [27], [33] | C1 |
| Enolase | 320±60/n.d. | 320±18/n.d. | 300±55/n.d. | C1,C2,C4 |
| Phospoenolpyruvate carboxylase | 63±18/56 [27], 16 [28] | 4±<1/n.d. | 6±1/8 [27] | C1 |
| Malate dehydrogenase | 3,000±350/913 [30], 600 [35] | 11,000±450/n.d. | 8,825±714/1,263 [30], 1,616 [35] | C1,C2,C4 |
| Malate-CoA ligase | 10±2/40 [29], 50 [36] | 3±0.3/n.d. | 3±0.3/n.d. | C1 |
| Malyl-CoA/β-methylmalyl-CoA lyase1 | 2,500±230/440 [27], 1,650 [37] | 410±40/n.d. | 400±50/80 [27], 300 [37] | C1,C2 |
| ETHYLMALONYL-CoA PATHWAY | ||||
| β-Ketothiolase | 100±5/n.d. | 390±7/n.d. | 560±50/392 [38] | C1,C2,C4 |
| Acetoacetyl-CoA reductase | 290±50/n.d. | 340±26/n.d. | 390±14/13 [38] | |
| Crotonase | 80±13/n.d. | 87±5/n.d. | 76±2/25 [38] | |
| Crotonyl-CoA carboxylase/reductase | 570±80/800 [14] | 240±0/n.d. | 190±20/200 [14] | C1,C2 |
| Ethylmalonyl-CoA mutase | 73±10/n.d. | 17±1/n.d. | 13±2/n.d. | C1,C2 |
| Methylsuccinyl-CoA dehydrogenase | 160±20/n.d. | 40±2/n.d. | 13±2/n.d. | C1,C2 |
| Mesaconyl-CoA hydratase | 210±50/n.d. | 180±0/n.d. | 52±22/n.d. | C1,C2 |
| Malyl-CoA/β-methylmalyl-CoA lyase2 | 650±60/n.d. | 130±10/n.d. | 86±8/n.d. | C1,C2 |
| Propionyl-CoA carboxylase | 74±2/26 [17] | 49±3/n.d. | 49±2/n.d. | C1,C2,C4 |
| Methylmalonyl-CoA mutase | 74±9/280 [39] | 45±5/n.d. | 32±3/8–16 [40] | |
| Malyl-CoA thioesterase | 26±12/n.d. | 120±75/n.d. | 61±20/n.d. | C2 |
*The values shown are means ± standard deviations of results from at least three independent measurements.
#
n. d. = not determined.
1
cleavage of malyl-CoA;
2
cleavage of β-methylmalyl-CoA.