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81.
In Vitro Release of Endogenous β- Alanine, GABA, and Glutamate, and Electrophysiological Effect of β-Alanine in Pigeon Optic Tectum 总被引:6,自引:6,他引:0
Gerhard Toggenburger Dominik Felix Michel Cuénod Hermann Henke 《Journal of neurochemistry》1982,39(1):176-183
The efflux of 20 amino acids, induced by either high K+ concentration or veratrine, was determined in pigeon tectal slices. Ca2+-dependent, K+-induced release of beta-alanine, gamma-aminobutyric acid (GABA), and glutamate was observed. Veratrine caused release of the same amino acids plus glycine in a tetrodotoxin-sensitive manner. beta-Alanine had a strong inhibitory effect on the activity of tectal neurons which was blocked by strychnine but not by bicuculline. The results indicated a transmitter function for beta-alanine in the optic tectum, and were consistent with the previously proposed transmitter role of GABA and glutamate in this structure. 相似文献
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α-Satellite DNA from African green monkey cells was analysed with restriction nucleases in some detail confirming and complementing our earlier results. With EcoRI and HaeIII (or BsuRI isoschizomer), about 25 and 10%, respectively, of the satellite DNA were cleaved into a series of fragments of the 172 bp repeat length and multiples thereof. To allow studies with fragments of homogeneous sequence unit length, HindIII fragments were covalently joined with the plasmid pBR313. After transformation 19 clones were obtained, containing up to three monomer fragments. Nine of the clones were characterized by digestion with EcoRI. Three of these had cleavage sites for this nuclease in the satellite DNA portion. In the six clones tested with HaeIII no cleavage site was detected in the cloned DNA. The results are discussed in relation to the nucleotide sequence data recently published by Rosenberg et al. (1978) and in the context of random and nonrandom processes in satellite DNA evolution. 相似文献
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The application of rotating frame spin-lattice relaxtion to the determination of the intramolecular motions in peptides is discussed, and results are presented on the application of 13C T1p to peptide microdynamics in solution. The effective molecular rotational reorientation times at the amide and amino nitrogens may be derived from appropriate data onT1p of the carbons adjacent to them. We also show by theoretical caculations that 1H and 13C T1p experiments of suitable 2H and 15N substituted peptides will allow intramolecular main- and sidechain motions, characterized by times in the range 10?1–10?6 sec, to be investigated. 相似文献
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B Wiederanders S Ansorge P Bohley U Broghammer H Kirschke J Langner 《Acta biologica et medica Germanica》1976,35(3-4):269-283
The preparation and properties of cathepsin D from rat liver are reported. The enzyme is an endopeptidase of lysosomal origin. The molecular weight was estimated to be 49000 by sodium-dodecylsulfate electrophoresis. We did not find any dissociation into subunits under reducing conditions, in contrast to some other authors. We found the enzyme to occur in at least 4 forms with the isoelectric points 5.87, 5.65, 5.41 and 5.13. Strong -SH-blocking reagents inhibit the activity, but the most powerful and specific inhibitor was pepstatin (Ki=38 nM). The substrate specificity is discussed. There was no proof for any zymogen activation in a great number of experiments. Since the cathepsins B1, B3 and L obviously seem to play the major role in the intracellular protein breakdown within the rat liver, the main task of cathepsin D is the degradation of extracellular proteins in this organ. 相似文献
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