scholarly journals The metabolism of neuropeptides. Endopeptidase-24.11 in human synaptic membrane preparations hydrolyses substance P

1985 ◽  
Vol 228 (2) ◽  
pp. 487-492 ◽  
Author(s):  
R Matsas ◽  
M Rattray ◽  
A J Kenny ◽  
A J Turner
Keyword(s):  
Substance P ◽  
Human Brain ◽  
Choroid Plexus ◽  
Synaptic Membranes ◽  
Synaptic Membrane ◽  
Immunoradiometric Assay ◽  
Endopeptidase 24.11 ◽  
Pig Brain ◽  
Enzymic Assay

Synaptic membrane preparations from human striatum and human diencephalon were shown to contain a phosphoramidon-sensitive metalloendopeptidase that appeared identical with endopeptidase-24.11. The activity of endopeptidase-24.11 was determined with an enzymic assay employing [D-Ala2,Leu5]enkephalin as substrate, and its distribution in human brain was similar to that in pig brain, with the striatum containing the highest levels. The choroid plexus and pons also contained substantial activity. A good correlation (r = 0.97) was obtained for the distribution of the endopeptidase in pig brain and pituitary by the enzymic assay and by an immunoradiometric assay specific for pig endopeptidase-24.11. Synaptic membrane preparations from human striatum and diencephalon hydrolysed substance P at the same sites as did preparations of pig striatal synaptic membranes, and hydrolysis was substantially abolished by phosphoramidon. These results suggest that endopeptidase-24.11 is the principal enzyme hydrolysing substance P in human synaptic membrane preparations.

scholarly journals The metabolism of neuropeptides. Neurokinin A (substance K) is a substrate for endopeptidase-24.11 but not for peptidyl dipeptidase A (angiotensin-converting enzyme)

1985 ◽  
Vol 231 (2) ◽  
pp. 357-361 ◽  
Author(s):  
N M Hooper ◽  
A J Kenny ◽  
A J Turner
Keyword(s):  
Substance P ◽  
Selective Inhibitor ◽  
Synaptic Membranes ◽  
Neurokinin A ◽  
Pig Kidney ◽  
Endopeptidase 24.11 ◽  
The Family ◽  
General Capacity ◽  
Substance K ◽  
Hydrolysis Of

Both endopeptidase-24.11 and peptidyl dipeptidase A have previously been shown to hydrolyse the neuropeptide substance P. The structurally related peptide neurokinin A is also shown to be hydrolysed by pig kidney endopeptidase-24.11. The identified products indicated hydrolysis at two sites, Ser5-Phe6 and Gly8-Leu9, consistent with the known specificity of the enzyme. The pattern of hydrolysis of neurokinin A by synaptic membranes prepared from pig striatum was similar to that observed with purified endopeptidase-24.11, and hydrolysis was substantially abolished by the selective inhibitor phosphoramidon. Peptidyl dipeptidase A purified from pig kidney was shown to hydrolyse substance P but not neurokinin A. It is concluded that endopeptidase-24.11 has the general capacity to hydrolyse and inactivate the family of tachykinin peptides, including substance P and neurokinin A.

scholarly journals An immunoradiometric assay for endopeptidase-24.11 shows it to be a widely distributed enzyme in pig tissues

1985 ◽  
Vol 228 (1) ◽  
pp. 119-126 ◽  
Author(s):  
N S Gee ◽  
M A Bowes ◽  
P Buck ◽  
A J Kenny
Keyword(s):  
Anterior Pituitary ◽  
Peritoneal Macrophages ◽  
Kidney Cortex ◽  
Lymphoid Tissues ◽  
Immunoradiometric Assay ◽  
Optimum Conditions ◽  
Endopeptidase 24.11 ◽  
Detergent Treatment ◽  
Enzymic Assay ◽  
Peripheral Blood Leucocytes

An immunoradiometric assay for endopeptidase-24.11, which depended on the absorption by tissues of a monoclonal antibody, GK7C2, was established. The optimum conditions for the assay were defined and its correlation with an enzymic assay determined. The immunoassay was used to survey the endopeptidase in crude homogenates of various tissues of the pig. Detergent treatment decreased the sensitivity of the assay but did not invalidate it. Although the endopeptidase was found in many tissues, it was neither uniformly nor ubiquitously distributed. Kidney cortex was confirmed as the major location of the endopeptidase, containing 5000 ng/mg of protein. Lymph nodes were also very active (1370 ng/mg), followed by chondrocytes from articular cartilage (650 ng/mg). In the gut, the endopeptidase was concentrated mainly in the jejunum (130 ng/mg). Various glands (salivary, adrenal, anterior pituitary and pancreas) also contained the antigen in the range 20-55 ng/mg of protein. Lung contained only 5 ng/mg of protein and, in other tissues examined, little or none was detectable. In particular, other lymphoid tissues (spleen, thymus, tonsillar tissues) were relatively poor sources, and none was detectable in peripheral-blood leucocytes or in peritoneal macrophages.

scholarly journals Neuropeptide-degrading endopeptidase activity of locust (Schistocerca gregaria) synaptic membranes

1988 ◽  
Vol 255 (3) ◽  
pp. 843-847 ◽  
Author(s):  
R E Isaac
Keyword(s):  
Schistocerca Gregaria ◽  
Physiological Role ◽  
Aminopeptidase Activity ◽  
Synaptic Membranes ◽  
Synaptic Membrane ◽  
Adipokinetic Hormone ◽  
Peptide Bonds ◽  
Endopeptidase 24.11 ◽  
Endopeptidase Activity ◽  
Neural Membranes

Locust adipokinetic hormone (AKH, pGlu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2) was used as the substrate to measure neuropeptide-degrading endopeptidase activity in neutral membranes from ganglia of the locust Schistocerca gregaria. Initial hydrolysis of AKH at neural pH by peptidases of washed neural membranes generated pGlu-Leu-Asn and Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2 as primary metabolites, demonstrating that degradation was initiated by cleavage of the Asn-Phe bond. Amastatin protected the C-terminal fragment from further metabolism by aminopeptidase activity without inhibiting AKH degradation. The same fragments were generated on incubation of AKH with purified pig kidney endopeptidase 24.11, and enzyme known to cleave peptide bonds that involve the amino group of hydrophobic amino acids. Phosphoramidon (10 microM), a selective inhibitor of mammalian endopeptidase 24.11, partially inhibited the endopeptidase activity of locust neural membranes. This phosphoramidon-sensitive activity was shown to enriched in a synaptic membrane preparation with around 80% of the activity being inhibited by 10 microM-phosphoramidon (IC50 = 0.2 microM). The synaptic endopeptidase was also inhibited by 1 mM-EDTA, 1 mM-1,10-phenanthroline and 1 microM-thiorphan, and the activity was maximal between pH 7.3 and 8.0. Localization of the phosphoramidon-sensitive enzyme in synaptic membranes is consistent with a physiological role for this endopeptidase in the metabolism of insect peptides at the synapse.

Characterization and quantification of 125I-bolton hunter substance P binding sites in human brain

1991 ◽  
Vol 18 (3) ◽  
pp. 399-404 ◽  
Author(s):  
Lars Nilsson ◽  
Bengt Winblad ◽  
Inga Volkmann ◽  
Irina Alafuzoff ◽  
Lena Bergström
Keyword(s):  
Substance P ◽  
Human Brain ◽  
Binding Sites

Characterization of two splice variants of human organic anion transporting polypeptide 3A1 isolated from human brain

2007 ◽  
Vol 292 (2) ◽  
pp. C795-C806 ◽  
Author(s):  
Robert D. Huber ◽  
Bo Gao ◽  
Marguerite-Anne Sidler Pfändler ◽  
Wenting Zhang-Fu ◽  
Simone Leuthold ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Brain ◽  
Frontal Cortex ◽  
Choroid Plexus ◽  
Splice Variants ◽  
Organic Anion ◽  
Xenopus Laevis Oocytes ◽  
Organic Anion Transporting Polypeptide ◽  
Human Frontal Cortex ◽  
Choroid Plexus Epithelial

In the present study we isolated two splice variants of organic anion transporting polypeptide 3A1 (OATP3A1_v1 and OATP3A1_v2) from human brain. OATP3A1_v2 lacks 18 amino acids (aa) at the COOH-terminal end (692 aa) but is otherwise similar in sequence to OATP3A1_v1 (710 aa). OATP3A1_v1 exhibits a wide tissue distribution, with expression in testis, various brain regions, heart, lung, spleen, peripheral blood leukocytes, and thyroid gland, whereas OATP3A1_v2 is predominantly expressed in testis and brain. On the cellular and subcellular levels OATP3A1_v1 could be immunolocalized in testicular germ cells, the basolateral plasma membrane of choroid plexus epithelial cells, and neuroglial cells of the gray matter of human frontal cortex. Immunolocalization of OATP3A1_v2 included Sertoli cells in testis, apical and/or subapical membranes in choroid plexus epithelial cells, and neurons (cell bodies and axons) of the gray and white matter of human frontal cortex. The rodent ortholog Oatp3a1 was also widely distributed in rat brain, and its localization included somatoneurons as well as astroglial cells. Transport studies in cRNA-injected Xenopus laevis oocytes and in stably transfected Chinese hamster ovary FlpIn cells revealed a similar broad substrate specificity for both splice variants. Transported substrates include prostaglandin (PG)E1 and PGE2, thyroxine, and the cyclic oligopeptides BQ-123 (endothelin receptor antagonist) and vasopressin. These studies provide further evidence for the involvement of OATPs in oligopeptide transport. They specifically suggest that OATP3A1 variants might be involved in the regulation of extracellular vasopressin concentration in human brain and thus might influence the neuromodulation of neurotransmission by cerebral neuropeptides such as vasopressin.

Serotonin and substance P co-exist in dorsal raphe neurons of the human brain

Neuroreport ◽  
1999 ◽  
Vol 10 (18) ◽  
pp. 3967-3970 ◽  
Author(s):  
Valeriy Sergeyev ◽  
Tomas Hökfelt ◽  
Yasmin Hurd
Keyword(s):  
Substance P ◽  
Human Brain ◽  
Dorsal Raphe ◽  
Dorsal Raphé ◽  
Raphe Neurons
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