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11.
A mass-spectrometric sequence study of the enzyme ribitol dehydrogenase from Klebsiella aerogenes 总被引:10,自引:6,他引:4
Howard R. Morris Dudley H. Williams Graeme G. Midwinter Brian S. Hartley 《The Biochemical journal》1974,141(3):701-713
The first detailed results of the application of a low-resolution mixture analysis approach to the sequence analysis of an enzyme, ribitol dehydrogenase, are given. Examples of the interpretation of the spectra of peptide mixtures derived from this protein are described. Evidence for new fragmentation patterns observed is reported, together with an explanation of the generation of ambiguous sequences by use of a low-specificity enzyme, thermolysin. The overall sequencing strategy evolved is assessed. 相似文献
12.
Three distinct antipeptide antisera generated against synthetic peptides that represent parts of the primary sequence of the alpha-subunit of the (pertussis toxin-sensitive) guanine nucleotide binding protein G0 were used in two-dimensional immunoblots of membranes of neuroblastoma X glioma (NG108-15) cells. Each antiserum identified two distinct polypeptides of some 39 kDa. These had apparent isoelectric points of 5.5 and 5.8. Differentiation of NG108-15 cells in response separately to dibutyryl cyclic AMP (cAMP), 8-bromo cAMP, forskolin, and prostaglandin E1 produced elevated levels of G0 alpha, as has previously been noted in one-dimensional immunoblots. Two-dimensional analysis demonstrated that the cAMP-induced increases in levels of G0 alpha were only of the more acidic isoform. The two isoforms were both substrates for pertussis toxin-catalysed ADP-ribosylation and did not appear to represent differentially phosphorylated forms of the same polypeptide. Separation of the two forms of G0 alpha could be achieved in one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis when 4 M deionized urea was included in the resolving gel. The more slowly migrating band was the acidic form and corresponded exactly in mobility with the major form of G0 from both rat and mouse brain. There was no equivalent in brain of the more rapidly migrating form of G0 from the cells. In agreement with the data from two-dimensional gels, only the more slowly migrating form was expressed in considerably higher amounts following cAMP-induced differentiation of NG108-15 cells. Of these two forms of "G0," the acidic species is equivalent to G0 from brain, but the basic form is not identical with G0*, which has been purified from bovine brain. 相似文献
13.
Michael J. Tyler Margaret Davies Graeme F. Watson David J. Williams 《Hydrobiologia》1996,318(3):135-137
The program BIOCLIM predicts the total geographic distribution of species, based upon the biogeoclimatic characteristics common to the localities at which they are known to occur. Field studies in the Northern Territory have located the Shield Shrimp Triops australiensis at localities substantially north of its known and predicted geographic distribution. 相似文献
14.
The indirect immunofluorescence technique was used to determine the distribution of peptide-containing axons in the gall bladder of the cane toad, Bufo marinus. In addition, the adrenergic innervation of the gall bladder was examined by use of immunoreactivity to the catecholamine-synthesizing enzyme, tyrosine hydroxylase, and glyoxylic acid-induced fluorescence. On the basis of peptide coexistence, two intrinsic populations of neurones and their projecting fibres could be distinguished substance P neurones and vasoactive intestine peptide neurones. Neither of these two types of neurones contained any other colocalized neuropeptides. Four populations of nerve fibres arising from cell bodies outside the gall bladder were identified: nerves containing colocalized galanin, somatostatin and vasoactive intestinal peptide; nerves containing colocalized calcitonin gene-related peptide and substance P; adrenergic nerves containing neuropeptide Y; and nerves containing only adrenaline. 相似文献
15.
16.
Vascular smooth muscle cell membranes from prehypertensive rats of the Milan hypertensive strain (MHS) were used to examine adenylyl cyclase activity and its regulation by guanine nucleotide regulatory proteins (G-proteins). Basal adenylyl cyclase activity was similar in MHS and Milan normontensive strain (MNS) membranes. Forsokolin (10?4 M) produced a significantly greater stimulatory response in MHS membranes, but this was not observed with NaF (10?2 M). Isoporterenol (10?4 M) caused a significantly decreased stimulation of adenylyl cyclase activity in MHS membranes, while prostaglandin E1 (10?5 M) produced similar responses in the two strains. Gi function and GTP responses, as observed by biphasic effects of GTP on isoproterenol-stimulated membranes, were similar in both strains. The levels of Gi2α and Gqα/G11α were similar in the two strains, while the levels of Gsα (44 and 42 kDa forms) and the β-subunit were significantly reduced by ~20% in MHS membranes. The α-subunit of Gi3 was dramatically reduced by ~80% in MHS membranes. The affinities of β-adrenergic receptors for the antagonist, cyanophindolol, were similar in the two strains; however, the number of β-adrenoceptors was substantially reduced in MHS membranes. These findings may be of relevance to altered vascular reactivity and transmembrane ion distribution observed in the MHS. 相似文献
17.
Graeme Milligan 《Journal of neurochemistry》1993,61(3):845-851
Abstract: Levels of the guanine nucleotide binding proteins G11α and Gqα, which produce receptor regulation of phosphoinositidase C., were measured immunologically in 13 regions of rat central nervous system. This was achieved by immunoblotting membranes from these regions with antisera (CQ series) that identify these two polypeptides equally, following separation of the membranes using sodium dodecyl sulphate-polyacrylamide gel electrophoresis conditions that can resolve Gqα and G11α. In all regions examined, Gqα was more highly expressed than G11α. Ratios of levels of Gqα to G11α varied between the regions from 5:1 to 2:1. Quantitative measurements of the levels of Gqα and G11α in each region were obtained by comparison with known amounts of purified liver Gqα and G11α and with E. coli expressed recombinant Gqα. Areas that expressed Gqα highly included olfactory bulb (930 ng/ mg of membrane protein), frontal cortex (700 ng/mg of membrane protein), parietal occipital cortex (670 ng/mg of membrane protein), caudate putamen (1,003 ng/mg of membrane protein), hippocampus (1,045 ng/mg of membrane protein), hypothalamus (790 ng/mg of membrane protein), and cerebellum (950 ng/mg of membrane protein). More modest levels were observed in thalamus (450 ng/mg of membrane protein), pituitary (480 ng/mg of membrane protein), optic chiasma (330 ng/mg of membrane protein), and spinal cord (350 ng/mg of membrane protein). Gna was more evenly expressed with values ranging from about 170 ng/mg of membrane protein in spinal cord and optic chiasma to close to 300 ng/mg of membrane protein in regions expressing high levels of Gqα. A third polypeptide could be identified by the CQ antisera in all brain regions. The possibility that this polypeptide is the α subunit of G14 is discussed. 相似文献
18.
Bishop Rosie R. Kubiak-Martens Lucy Warren Graeme M. Church Mike J. 《Vegetation History and Archaeobotany》2023,32(1):65-83
Vegetation History and Archaeobotany - This paper presents new evidence for the harvesting of edible plant roots and tubers at Northton, a Mesolithic hunter-gatherer site on Harris, in the Western... 相似文献
19.
The direct resolution of enantiomers of a series of imidazol-2-yl-substituted alcohols has been achieved by gas chromatography on a well-deactivated fused-silica capillary column, coated with L -Chirasil-Val as the chiral stationary phase. The separation of these basic compounds is accomplished without exaggerated peak tailing. Compared to simpler alcohols the resolution factors (α) observed are extraordinarily large. While the imidazolyl substituent may contribute to the mechanism of the chiral discrimination, the crucial interaction is assumed to be through the hydroxy group, based on the observation that the resolution factors for the corresponding O-acetyl derivatives are markedly reduced. © 1993 Wiley-Liss, Inc. 相似文献
20.
Irina Zaitseva Vjacheslav Zaitsev Graeme Card Kirill Moshkov Benjamin Bax Adam Ralph Peter Lindley 《Journal of biological inorganic chemistry》1996,1(1):15-23
The X-ray structure of human serum ceruloplasmin has been solved at a resolution of 3.1?Å. The structure reveals that the molecule is comprised of six plastocyanin-type domains arranged in a triangular array. There are six copper atoms; three form a trinuclear cluster sited at the interface of domains 1 and 6, and there are three mononuclear sites in domains 2, 4 and 6. Each of the mononuclear coppers is coordinated to a cysteine and two histidine residues, and those in domains 4 and 6 also coordinate to a methionine residue; in domain 2, the methionine is replaced by a leucine residue which may form van der Waals type contacts with the copper. The trinuclear centre and the mononuclear copper in domain 6 form a cluster essentially the same as that found in ascorbate oxidase, strongly suggesting an oxidase role for ceruloplasmin in the plasma. 相似文献