KECK K, CHOULES E A
J Cell Biol. 1963 Aug;18(2):459-69. doi: 10.1083/jcb.18.2.459.
Several species-specific molecular forms of acid phosphatase are known to exist in the unicellular green alga Acetabularia. In graft combinations between cells of Acetabularia mediterranea (med) and Acicularia Schenckii (acic) the expression of the med phosphatase is dominant over acic phosphatase. There is good evidence that in such grafts the preexisting acic phosphatase is converted on the molecular level via an intermediate form to the med phosphatase. This conversion can be initiated by the transplantation of a med cell nucleus to an anucleate acic cell, but will also take place in grafts between anucleate med and anucleate acic cells, indicating that the direct participation of a cell nucleus is not required. An incomplete conversion of acic phosphatase, which terminates at the intermediate stage, is induced in acic cells by injection of a concentrated homogenate of med cytoplasm. A similar partial conversion occurs in vitro in a mixture of homogenates from med and acic cells. Subcellular particles, such as chloroplasts or mitochondria, can be removed from the homogenates by centrifugation without impairing the reactions leading to the intermediate phosphatase type. Experimental evidence suggests that the transformation of phosphatase types is enzymatically catalyzed and may involve the conjugation of small molecules with the phosphatase protein. It was shown, however, that sialic acid is not involved, since the incubation of med or acic homogenates with neuraminidase did not modify the electrophoretic mobility of either enzyme type. Another type of phosphatase, which occurs in Acetabularia erenulata (cren) and can be distinguished electrophoretically from the aforementioned types, is not subject to interaction. In various mono- and multi-nucleate graft combinations between cren cells on one hand, and med or acic cells on the other hand, the cren phosphatase is synthesized independently of the enzyme of the graft partner.
已知单细胞绿藻伞藻中存在几种物种特异性的酸性磷酸酶分子形式。在地中海伞藻（med）和针形伞藻（acic）细胞之间的嫁接组合中，med磷酸酶的表达相对于acic磷酸酶占主导地位。有充分证据表明，在这种嫁接中，预先存在的acic磷酸酶在分子水平上通过一种中间形式转化为med磷酸酶。这种转化可以通过将med细胞核移植到去核的acic细胞中来启动，但也会在去核的med细胞和去核的acic细胞之间的嫁接中发生，这表明不需要细胞核的直接参与。通过注射浓缩的med细胞质匀浆，在acic细胞中诱导acic磷酸酶的不完全转化，该转化在中间阶段终止。在med和acic细胞匀浆的混合物中，体外也会发生类似的部分转化。亚细胞颗粒，如叶绿体或线粒体，可以通过离心从匀浆中去除，而不会损害导致中间磷酸酶类型的反应。实验证据表明，磷酸酶类型的转化是由酶催化的，可能涉及小分子与磷酸酶蛋白的结合。然而，已表明唾液酸不参与其中，因为用神经氨酸酶孵育med或acic匀浆不会改变任何一种酶类型的电泳迁移率。另一种磷酸酶类型存在于细圆齿伞藻（cren）中，并且可以通过电泳与上述类型区分开来，它不受相互作用的影响。在一方面是cren细胞，另一方面是med或acic细胞的各种单核和多核嫁接组合中，cren磷酸酶的合成独立于嫁接伙伴的酶。
