Sidney Udenfriend

Purification and partial sequencing of human placental alkaline phosphatase

Two forms of human placental alkaline phosphatase have been purified to homogeneity utilizing high performance liquid chromatography. Both have the same amino acid composition but they differ in their carbohydrate substituents. Sequence data indicate that the two forms are identical for the first forty two residues from the amino terminus are presented.

THE ANATOMICAL CHARACTERISTICS OF DOPAMINE-β-HYDROXYLASE ACCUMULATION IN LIGATED SCIATIC NERVE

The anatomical characteristics of the accumulation of dopamine-β-hydroxylase (DBH) that occurs after ligation of rat sciatic nerve were examined in detail using a recently developed specific immunofluorescence method. Although rapid accumulation of DBH occurred showing the presence of axonal transport, the anatomical observations indicated that the build-up was considerably more complex than the simple blockade model frequently used as a basis for computation of transport rates from quantitative estimates of accumulation. During the early time period (7 hr) the situation was complicated by a substantial amount of accumulation of DBH distal to the ligation. By 24 hr after ligation the distal accumulation was small compared to that present proximally. The size of the discrete areas covered by DBH fluorescence at 24 hr indicated that axonal membranes may have already started to rupture, thus releasing vesicles into the extracellular space. By 48 hr after ligation the DBH was no longer confined to the area near the ligation, but extended 3.6 mm proximally. By 96 hr after ligation there had been a net loss of DBH fluorescence indicating that degradation and clearance of accumulated DBH had occurred.

The Enkephalin-Containing Peptides

There are three known genes that code for enkephalin-containing (EC) peptides (Udenfriend and Kilpatrick, 1983). The one coding for proenkephalin is expressed in many tissues. Having characterized many of the proenkephalin products and developed methods for their assay (Udenfriend et al., 1983), and having cloned bovine (Gubler et al., 1982) and rat (Howells et al., 1984) proenkephalin cDNA, we had the tools to investigate the biology of this EC peptide precursor.