Department of Bacteriology and Biochemistry, University of Idaho, Moscow, Idaho 83843.
Plant Physiol. 1990 Oct;94(2):833-9. doi: 10.1104/pp.94.2.833.
The glycine decarboxylase multienzyme complex comprises about one-third of the soluble protein of the matrix of pea (Pisum sativum) leaf mitochondria where it exists at a concentration of approximately 130 milligrams protein/milliliter. Under these conditions the complex is stable with an approximate subunit ratio of 2 P-protein dimers:27 H-protein monomers:9 T-protein monomers:1 L-protein dimer. When the complex is diluted it tends to dissociate into its component enzymes. This prevents the purification of the intact complex by gel filtration or ultracentrifugation. In the dissociated state the H-protein acts as a mobile cosubstrate that commutes between the other three enzymes and shows typical substrate kinetics. When the complex is reformed, the H-protein no longer acts as a substrate but as an integrated part of the enzyme complex.
甘氨酸脱羧酶多酶复合物约占豌豆（Pisum sativum）叶线粒体基质中可溶性蛋白的三分之一，其浓度约为 130 毫克蛋白/毫升。在这些条件下，该复合物是稳定的，具有约 2 P-蛋白二聚体：27 H-蛋白单体：9 T-蛋白单体：1 L-蛋白二聚体的近似亚基比。当复合物被稀释时，它往往会解聚成其组成酶。这阻止了通过凝胶过滤或超速离心纯化完整的复合物。在解聚状态下，H-蛋白作为一种可移动的共底物，在其他三种酶之间交换，并表现出典型的底物动力学。当复合物重新形成时，H-蛋白不再作为底物，而是作为酶复合物的一个整合部分。
