Biomaterial Database

Neuronal N-acetyl-beta-D-glucosaminidase. Evidence for its biosynthesis in vitro. 1976

J A Khawaja, and O Z Sellinger

Neuronal cell bodies, isolated in bulk from 8-day-old rat cerebral cortices, were incubated in the presence of a 3H-labelled amino acid mixture, and subcellular fractions isolated by differential centrifugation. The particulate fractions were frozen/thawed in 0.20 M-sucrose/0.1 M-KCl [Selling et al. (1973) Biochim. Biophys. Acta 315, 128-146] and the profiles of acid-insoluble radioactivity and N-acetyl-beta-D-glucosaminidase (glucosaminidase) activity compared in the resulting non-sedimentable fractions by DEAE-cellulose chromatography and cellulose acetate electrophoresis. Radioactivity and glucosaminidase activity co-migrated to a significant extent. Electrophoresis revealed that after 1 min of incubation 42% of the radioactivity of the non-sedimentable microsomal fraction after freezing and thawing co-migrated with an intensely fluorescent band of glucosaminidase activity. Since the pellet fraction obtained on freezing/thawing the microsomal fraction contained up to 75% of the RNA, 95% of the radioactivity and 45% of the glucosaminidase, a detailed study of the association between its radioactivity and nascent glucosaminidase activity was undertaken. After 1 and 2 min of incubation, followed by centrifugation of the microsomal pellet on 35-60% (w/v) sucrose density gradients, radioactivity and glucosaminidase activity exhibited parallel profiles in the region of heavy polyribosomes and at the top of the gradient which contains spontaneously released nascent polypeptide chains. DEAE-cellulose chromatography of these chains revealed glucosaminidase A to be the principal nascent glucosaminidase component, with glucosaminidases B and C as minor peaks. After 2 min of incubation, all of the glucosaminidase components appeared labelled, and glucosaminidase A exhibited two distinct sub-components. The pattern of glucosaminidase labelling in the soluble and microsomal fractions suggested that newly formed glucosaminidase molecules traverse both the cellular sap and the lumen of the endoplasmic reticulum. Only glucosaminidase A reacted specifically with concanavalin A and radioactive glucosaminidase A could be successfully regenerated by treatment with alpha-methyl-D-glucoside. Glucosaminidase A and a substantial portion of the radioactivity associating with it could be readily converted into glucosaminidase B by re-chromatography on DEAE-cellulose and by reaction of the concanavalin A-glucosaminidase A complex with methyl glucosides.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008757	Methylglucosides		Methylglucopyranosides
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011132	Polyribosomes	A multiribosomal structure representing a linear array of RIBOSOMES held together by messenger RNA; (RNA, MESSENGER); They represent the active complexes in cellular protein synthesis and are able to incorporate amino acids into polypeptides both in vivo and in vitro. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Polysomes,Polyribosome,Polysome
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D003208	Concanavalin A	A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.
D004586	Electrophoresis	An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.	Electrophoreses
D006596	Hexosaminidases	Enzymes that catalyze the hydrolysis of N-acylhexosamine residues in N-acylhexosamides. Hexosaminidases also act on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES.	Galactosaminidases,Hexosaminidase,Galactosaminidase,Glucosaminidase,Glucosaminidases