Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

After homogenization of intestinal mucosa from vitamin D-replete chicks and high speed centrifugation, the major proportion of the vitamin D-induced calcium-binding protein is present in the supernatant fraction. However, the centrifugate, after repeated washing, contains significant amounts of bound calcium-binding protein that can be solubilized by Triton X-100. The bound calcium-binding protein is identical to soluble calcium-binding protein by the criteria of immunological identity, electrophoretic mobility, and molecular size, as determined by gel filtration chromatography. The bound calcium-binding protein is only partially released by sonication, osmotic shock or by ribonuclease treatment. Bound and soluble calcium-binding protein are not present in rachitic chick intestine. The addition of calcium-binding protein to rachitic mucosa prior to homogenization does not yield a Triton X-100 solubilizable form, indicating that bound calcium-binding protein in vitamin D-replete intestine is not due to adsorption or vesicular entrapment of soluble calcium-binding protein. The overall evidence suggests that part of the intestinal calcium-binding protein is membrane-bound.
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PMID:Evidence for a membrane-bound fraction of chick intestinal calcium-binding protein. 63 6

Undegraded polyribosome preparations may be obtained from chick intestinal mucosa if ribonuclease activity is strictly controlled. This is best achieved by homogenization of the mucosa directly in rat liver cell-sap. 2. The extent of amino acid incorporation by chick intestinal polyribosomes is greatly influenced by the source of the cell-sap. Sephadex-treated intestinal cell-sap caused impaired incorporation and release of completed polypeptide chains, whereas Sephadex-treated rat liver cell-sap promoted the polymerization of up to 90 amino acids per ribosome. Under optimum conditions 30-35% of the nascent polypeptide chains are completed and released. 3. The preparation of an antiserum against the calcium-binding protein formed in response to vitamin D is described. It is shown that the antiserum is highly specific for calcium-binding protein. 4. This antiserum was used to investigate the ability of chick intestinal polyribosomes to synthesize calciumbinding protein. Only polyribosomes from chicks receiving vitamin D have the ability to synthesize calcium-binding protein. Moreover, the product formed in vitro has the same electrophoretic mobility as calcium-binding protein synthesized in vivo. 5. It is concluded that one of the main functions of vitamin D in the small intestine is to induce the synthesis de novo of calcium-binding protein.
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PMID:The response of the small intestine to vitamin D. Isolation and properties of chick intestinal polyribosomes. 445 90

Double-labeling immunofluorescent histochemistry demonstrates that calretinin, a calcium-binding protein, coexists with calcitonin gene-related peptide, vasoactive intestinal peptide, and substance P in the fibers innervating the lamina propria of the rat intestinal villi. An acetylcholinesterase histochemical stain revealed that the majority of calretinin-containing cells in the myenteric ganglia were cholinergic and that about one half of the submucosal calretinin-containing cells colocalized with acetylcholinesterase. In situ hybridization studies confirmed the presence of calretinin mRNA in the dorsal root ganglia, and a ribonuclease protection assay verified the presence of calretinin message in the intestine. The coexistence of calretinin in calcitonin-gene-related-peptide-containing cells that also contained substance P and vasoactive intestinal polypeptide in the dorsal root ganglia suggest that these ganglia are the source of the quadruple colocalization within the sensory fibers of the villi. Although the function of calretinin in these nerves is unknown, it is hypothesized that the coexistence of three potent vasodilatory peptides influences the uptake of metabolized food products within the vasculature of the villi.
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PMID:Quadruple colocalization of calretinin, calcitonin gene-related peptide, vasoactive intestinal peptide, and substance P in fibers within the villi of the rat intestine. 754 20