John Innes Institute, Colney Lane, Norwich NR4 7UH, United Kingdom.
Plant Physiol. 1992 Aug;99(4):1626-34. doi: 10.1104/pp.99.4.1626.
A mutation at the rb locus of pea (Pisum sativum L.) alters the shape, reduces the starch content, and increases the lipid and sucrose contents of the seed. These effects are probably all consequences of a reduction of up to 40-fold in the maximum catalytic activity of ADP glucose pyrophosphorylase in the developing embryo of the mutant relative to the wild type. We have investigated how the mutation brings about this reduction in activity. The purified enzyme from mutant embryos has a specific activity about 10-fold lower than that from wild-type embryos, and it is much more sensitive to the effectors inorganic phosphate and 3-phosphoglycerate than the wild-type enzyme. Both wild-type and mutant enzymes consist of polypeptides of around 50 kilodaltons. One of the polypeptides of the purified wild-type enzyme is missing from the mutant enzyme. We deduce that in the wild-type embryo this protein may interact with other subunits to confer a high specific activity and a low susceptibility to effectors on the enzyme.
豌豆（Pisum sativum L.） rb 基因座的突变改变了种子的形状，降低了淀粉含量，增加了脂肪和蔗糖含量。这些影响可能都是由于突变体相对于野生型发育胚胎中 ADP 葡萄糖焦磷酸化酶最大催化活性降低了 40 倍所致。我们已经研究了突变如何导致这种活性降低。突变体胚胎中纯化的酶的比活约比野生型胚胎低 10 倍，并且比野生型酶对效应物无机磷和 3-磷酸甘油酸更为敏感。野生型和突变型酶均由约 50 千道尔顿的多肽组成。从突变体酶中缺失了纯化的野生型酶的一个多肽。我们推断，在野生型胚胎中，这种蛋白质可能与其他亚基相互作用，赋予酶高比活和低对效应物的敏感性。
