The original premise of the Editors in initiating this series was that there existed a readership ofneurochemists with considerable biochemical back- ground who would make use of a series dedicated to both new develop- ments and specialized reviews in neurochemistry. Having selected our authors, we have offered them virtually complete freedom to reflect and speculate in a field in which they have achieved prominence. The response to the first two volumes has been rewarding. The present one continues in this tradition. While we have not attempted to publish specialized volumes, the present volume contains two somewhat related chapters (Chapters 4 and 5, on the role of amino acid neurotransmitters). The first three chapters examine three diverse approaches, each of current interest, in neurochemi- cal approaches to the molecular bases of neuronal and glial structure. B. W. Agranoff M. H. Aprison vii CONTENTS CHAPTER 1 2',3'-CYCUC NUCLEOTIDE 3'-PHOSPHODIESTERASE NEIL RAYMOND SIMS AND PATRICK ROBERT CARNEGIE 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. Assay of CNPase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. 1. Need for Activation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. 2. Comparison of Assays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Association of CNPase with Myelin . . . . . . . . . . . . . . . . . . . . . . . 7 3. 1. Historical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. 2. Subcellular Fractionation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. 3. Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. 4. Mutant Mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3. 5. Use as a Myelin Marker . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3. 6. Myelin-Related Fractions and Peripheral Nerve Myelin. 11 4. CNPase in Nonmyelin Fractions. . . . . . . . . . . . . . . . . . . . . . . . . . 13 5. Activation and Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5. 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5. 2. Activation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5. 3. Solubilization and Fractionation. . . . . . . . . . . . . . . . . . . . . . 15 6. Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6. 1. Substrate Specificity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .