摘要:

Abstract:In vivo phosphorylation of axonal proteins was investigated in normal and regenerating optic nerves of goldfish by two‐dimensional gel electrophoresis. By 6–24 h after intraocular injection of H332PO4, ˜ 20 optic nerve proteins ranging in size from 19 to 180 kilodaltons and in pI from 4.4 to 6.8 were seen to have incorporated radiolabel. Five of these proteins showed a robust increase in incorporation of phosphate during regeneration. Among the latter was an acidic (pI 4.5) 45‐kilodalton protein, which has previously been shown to be conveyed by fast axonal transport and to increase dramatically in its rate of synthesis during regeneration of goldfish optic

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13159.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Abstract:Brain contains a membrane‐bound form of endopeptidase‐24. 15, a metalloendopeptidase predominantly associated with the soluble protein fraction of brain homogenates. Subcellular fractionation of the enzyme in rat brain showed that 20–25% of the total activity is associated with membrane fractions including synaptosomes. Solubilization of the enzyme from synaptosomal membranes required the use of detergents or treatment with trypsin. The specific activity of the enzyme in synaptosomal membranes measured with tertiary‐butoxycarbonyl‐Phe‐Ala‐Ala‐Phe‐p‐aminobenzoate as substrate was higher than that of endo‐peptidase‐24.11 (“enkephalinase”), a membrane‐bound zinc‐metalloendopeptidase believed to function in brain neuropeptide metabolism. Purified synaptosomal membranes converted efficiently dynorphini1‐8, α‐and β‐neoen‐dorphin into leucine enkephalin and methionine‐enkepha‐Iin‐Arg6‐Gly7‐Leu8into methionine enkephalin in the presence of captopril, bestatin, and N‐[l‐ (R, S)‐carboxy‐2‐phenylethyl]‐Phe‐p‐aminobenzoate, inhibitors of angiotensin converting enzyme (EC 3.4.15.1), aminopeptidase (EC 3.4.11.2), and membrane‐bound metalloendopeptidase (EC 3.4.24.11), respectively. The conversion of enkephalin‐containing peptides into enkephalins was virtually completely inhibited byN‐[l‐ (R, S)‐carboxy‐2‐phenylethyl]‐Ala‐Ala‐Phe‐p‐aminobenzoate, a specific active‐site‐directed inhibitor of endopeptidase‐24.15, indicating that this enzyme was responsible for the observed interconversions. The data indicate that synaptosomal membranes

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13160.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Abstract:Luteinizing hormone‐releasing hormone was degraded by cells of the N‐ I8 line of mouse neuroblastoma and their membrane. Cleavage products were separated by HPLC and identified by amino acid analysis. Fragments (1‐3), (4‐5), and (6‐10) were major cleavage products. All the products increased in level as a function of time except for fragment (1‐9, which increased in amount only during a short incubation time and then decreased. The accumulation of fragment (1‐5) was increased in the presence of captopnl or EDTA, whereas that of fragments (1‐3) and (4‐5) decreased inversely. On the other hand, the generation of either fragment (1‐3) or (4‐5) was stimulated by the presence of C1‐. The results suggest that the conversion of fragment (1‐5) into fragments (1‐3) and (4‐5) is catalyzed by angiotensin‐converting enzyme. p‐Chloromercuribenzoate inhibited the formation of fragment (1‐5), a result suggesting the involvement of a thiol protease in this formation. Thus, the degradation of luteinizing hormone‐releasing hormone by neuroblastoma cells and their membrane seems to take place mainly through the cleavage of the Tyr5‐Gly6bond by a thiol protease, followed by the release of the dipeptide Ser‐Tyr from the liberated fragment (1‐5) by angotensin‐converting enzyme. It is further suggested that the thiol protease and angiotensin‐converting enzyme are also responsible for the initial minor cleavages of the Gl

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13161.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Abstract:The distribution of glial fibrillary acidic protein (GFAP) into cytoskeletal and soluble protein fractions during development of the rat brain has been studied by quantitative immunoblotting and enzyme‐linked immunosorbent assay (ELISA). These assays indicate that cytoskeletal GFAP accounts for nearly all the total GFAP in the adult rat brain, and that the developmental increase in the GFAP content of the rat brain is due to accumulation of GFAP into the cytoskeleton. A small and constant amount of the total GFAP was detected in the soluble protein fraction. This GFAP had an apparent molecular mass (Mr) similar to that of the highest Mrform of GFAP detected in the cytoskeletal fraction. In contrast to the assays for cytoskeletal GFAP, no significant increase in the GFAP concentration of the soluble protein fraction could be measured during development. Sensitive, calibrated immunoblotting of cytoskeletal and soluble protein with [125I]protein A confirmed these findings, and showed that both cytoskeletal and soluble GFAP are first detected during the same period of foetal rat brain development. A finite and reproducible amount of lower Mrforms of GFAP were observed in the cytoskeletal fraction even when prepared in the presence of stringent proteolytic inhibitors. These presumed proteolytic degradation products of GFAP increased in abundance during development, parallel to the increase in cytoskeletal GFAP content of the rat brain. However, the abundant proteolytic degradation products of GFAP found in the cytoskeletal fraction were not detected in the soluble protein fraction at any age studied. These findings, and the failure to detect a significant increase in the amount of soluble GFAP during development, strongly suggest that the very small pool of soluble GFAP is unlikely to be derived from the much larger pool of cytoskeletal GFAP. The possible role of soluble GFAP as a precursor to glial filaments is discusse

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13162.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Abstract:With the aim of selecting cDNA sequences expressed in neurons utilizing exclusively cholinergic synaptic transmission, cDNA derived fromTorpedoelectric lobe was cloned and screened by hybridization with probes originating from another brain region known for its low content of cholinergic neurons (cerebellum) and a nonneuronal tissue (muscle). This method led to the isolation of 18 clones among 3, 200 showing no hybridization with probes other than those derived from electric lobe. These clones can therefore be considered to represent sequences involved in the expression of cholinergic function in neurons.

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13163.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Abstract:Events leading to and the influences on the founding of the American Society for Neurochemistry are recounted, with emphasis on early activities of neurochemists in the United States, as well as the international activities, that led to the founding of both the International and American societies (in 1965 and 1969, respectively). The founding of the American Society for Neurochemistry in the period 1968–1969 and its first annual meeting in 1970 are described, together with significant developments during the early years of the Societ

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13164.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13166.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1987.tb13167.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY