Subcellular localization ofO-acetylserine sulfhydrylase in spinach leaves

Summary A combination of differential centrifugation and isopycnic sucrose density gradient centrifugation of extracts from spinach leaves (Spinacia oleracea L.) shows that about 20% of the O-Acetylserine sulfhydrylase are associated with chloroplasts. No appreciable amounts of O-Acetylserine sulfhydrylase band with mitochondrial and peroxisomal marker enzymes.This work was supported in part by the Swiss National Foundation (SNF), grant No. 3.610-0.75.     

Subcellular localization of O-acetylserine sulfhydrylase in spinach leaves.

A combination of differential centrifugation and isopycnic sucrose density gradient centrifugation of extracts from spinach leaves (Spinacia oleracea L.) shows that about 20% of the O-Acetylserine sulfhydrylase are associated with chloroplasts. No appreciable amounts of O-Acetylserine sulfhydrylase band with mitochondrial and peroxisomal marker enzymes.     

Chemical synthesis of a hexadecapeptide segment of ubiquitin that activates adenylate cyclase and induces lymphocytes to differentiate

Summary A hexadecapeptide corresponding to positions 59–74 of ubiquitin was synthesized and purified. The peptide was characterized by its mobility in TLC and electrophoresis, amino acid sequence and composition, and molar rotation. The peptide possessed approximately 40% activity compared with native ubiquitin in each of 3 biological assays in vitro: a) thymocyte induction, b) B cell induction and c) elevation of intracellular cyclic AMP levels in sarcoma 180 cells.Acknowledgments. We thank Dr Geoffrey Tregear for helpful suggestions for the synthesis strategy, Dr Jim Burton for guidance with the methods for establishing peptide purity, and Ronald King, Miriam Miller, Jeanette Dilley and Linda Townley for excellent technical assistance. This work was supported by U.S. Public Health Service Grants CA-08748, CA-16889, CA-08415, CA-17085 and AI-12487, and by NCI Contract CB-53868.     

Die Veränderung des Stärke-, Protein- und RNS-Gehaltes vonLemna minor L. unter dem Einfluss von Kinetin (6-Furfurylaminopurin)

Summary Kinetin (6-furfurylaminopurine) is rapidly absorbed byLemna minor L. 3 · 10^–8 M/ml medium cause an immediate but temporary stimulation of RNA and protein synthesis during the first hour of the treatment. The following excessive accumulation of starch is considered to be more or less a direct consequence of a disturbed RNA and protein metabolism.