Tanksley S D, Kuehn G D
Biochem Genet. 1985 Jun;23(5-6):441-54. doi: 10.1007/BF00499085.
Three independent genes are responsible for 6-phosphogluconate dehydrogenase (6PGDH) activity in tomato. 6Pgdh-2, located on chromosome 12, codes for subunits of an active dimer which is restricted to the plastids. 6Pgdh-1, chromosome 4, and 6Pgdh-3, chromosome 5, code for subunits which form three dimers--two homodimers and an intergenic heterodimer. The latter three isozymes are found in the cytosol. 6Pgdh-1, 6Pgdh-2, and 6Pgdh-3 code for subunits with estimated molecular weights of 49,500, 50,500, and 51,200, respectively. The intergenic heterodimer encoded by 6Pgdh-1 and 6Pgdh-3 is thus composed of subunits that differ in length by approximately 15 amino acid residues. Divergence in the length and primary subunit structure may account for the lower thermal stability of the intergenic heterodimer compared with the corresponding homodimers. A limited survey of other solanaceous plant species suggests that the duplication of cytosolic 6PGDH-coding genes found in tomato may be widespread in the family.
三个独立的基因负责番茄中6 - 磷酸葡萄糖酸脱氢酶（6PGDH）的活性。位于12号染色体上的6Pgdh - 2编码一种活性二聚体的亚基，该二聚体局限于质体。位于4号染色体上的6Pgdh - 1和位于5号染色体上的6Pgdh - 3编码形成三个二聚体的亚基——两个同型二聚体和一个基因间异型二聚体。后三种同工酶存在于细胞质中。6Pgdh - 1、6Pgdh - 2和6Pgdh - 3分别编码估计分子量为49,500、50,500和51,200的亚基。因此，由6Pgdh - 1和6Pgdh - 3编码的基因间异型二聚体由长度相差约15个氨基酸残基的亚基组成。长度和主要亚基结构的差异可能解释了基因间异型二聚体与相应同型二聚体相比热稳定性较低的原因。对其他茄科植物物种的有限调查表明，番茄中发现的细胞质6PGDH编码基因的重复在该科中可能很普遍。
