Vestal J R, Perry J J
J Bacteriol. 1969 Jul;99(1):216-21. doi: 10.1128/jb.99.1.216-221.1969.
The metabolism of propane and propionate by a soil isolate (Brevibacterium sp. strain JOB5) was investigated. The presence of isocitrate lyase in cells grown on isopropanol, acetate, or propane and the absence of this inducible enzyme in n-propanol- and propionate-grown cells suggested that propane is not metabolized via C-terminal oxidation. Methylmalonyl coenzyme A mutase and malate synthase are constitutive in this organism. The incorporation of (14)CO(2) into pyruvate accumulated during propionate utilization suggests that propionate is metabolized via the methyl-malonyl-succinate pathway. These results were further substantiated by radiorespirometric studies with propionate-1-(14)C, -2-(14)C, and -3-(14)C as substrate. Propane -2-(14)C was shown, by unlabeled competitor experiments, to be oxidized to acetone; acetone and isopropanol are oxidized in this organism to acetol. Cleavage of acetol to acetate and CO(2) would yield the inducer for the isocitrate lyase present in propane-grown cells.
对一株土壤分离菌（短杆菌属菌株JOB5）的丙烷和丙酸盐代谢进行了研究。在以异丙醇、乙酸盐或丙烷为碳源生长的细胞中存在异柠檬酸裂解酶，而在以正丙醇和丙酸盐为碳源生长的细胞中不存在这种诱导酶，这表明丙烷不是通过碳末端氧化进行代谢的。甲基丙二酰辅酶A变位酶和苹果酸合酶在该生物体中是组成型的。在丙酸盐利用过程中积累的丙酮酸中掺入（14）CO（2），这表明丙酸盐是通过甲基丙二酰琥珀酸途径进行代谢的。以丙酸盐-1-（14）C、-2-（14）C和-3-（14）C为底物的放射性呼吸测定研究进一步证实了这些结果。通过未标记竞争实验表明，丙烷-2-（14）C被氧化为丙酮；丙酮和异丙醇在该生物体中被氧化为乙酰醇。乙酰醇裂解为乙酸盐和CO（2）将产生在以丙烷为碳源生长的细胞中存在的异柠檬酸裂解酶的诱导物。
