Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An acidic, low molecular weight (18 400--19 100) protein capable of activating porcine brain phosphodiesterase in the presence of calcium has been purified 2700-fold from the anthozoan coelenterate, Renilla reniformis. The protein has physical, spectral, and chemical properties similar to those of modulator proteins isolated from mammalian species. Amino acid composition studies reveal no significant differences between the Renilla and mammalian modulator proteins. For example, we observed 1 mol of epsilon-N-trimethyllysine per mol of protein, no tryptophan or cysteine, and high levels of glutamic and aspartic acid residues. The protein from Renilla complexes with troponin I and T subunits in the presence of calcium and quantitatively replaces porcine brain modulator in the calcium-dependent activation of porcine brain phosphodiesterase. The protein has a high affinity for calcium as judged by the low levels of free calcium required for modulator-dependent activation of phosphodiesterase. The similarities in physical and chemical properties, high affinity for calcium, and identical calcium-dependent activities of this protein from Renilla (as compared with modulator protein purified from mammalian systems) suggest that a high degree of structural conservation has been retained in modulator proteins isolated from these diverse evolutionary forms.
...
PMID:Isolation and characterization of Ca2+-dependent modulator protein from the marine invertebrate Renilla reniformis. 3 94

A Ca2+-dependent regulator protein of cyclic 3':5'-nucleotide phosphodiesterase (EC 3.1.4.17) has previously been isolated from rat testis and shown to be a heat-stable, Ca2+-binding protein with a molecular weight of approximately 17,000. The Ca2+-dependent regulator protein is also structurally similar to troponin-C, the Ca2+-binding component of muscle troponin and Ca2+ mediator of muscle contraction. The present report describes a partial amino acid sequence of the Ca2+-dependent regulator. The protein (148 amino acids) is 50% homologous with skeletal muscle troponin-C, but is 11 residues shorter than the muscle protein. The Ca2+-dependent regulator protein has an NH2-terminal sequence of acetyl-Ala-Asp-Glu, a COOH-terminal sequence of Thr-Ala-Lys and 1 residue of epsilon-trimethyllysine located at position 115. All of these properties are distinct from those of other homologous Ca2+-binding proteins. These properties may account for the biological specificities demonstrated by these proteins as compared to the Ca2+-dependent regulator protein. Based on the sequence and a comparison of the Ca2+-dependent regulator protein to other calcium-binding proteins, our data support the view that all of these moecules contain common sequences, especially at their proposed metal-binding sites.
...
PMID:Sequence homology of the Ca2+-dependent regulator of cyclic nucleotide phosphodiesterase from rat testis with other Ca2+-binding proteins. 20 28

Bovine mammary gland calmodulin, purified by conventional fractionation procedures, was compared with similarly purified bovine brain calmodulin. Affinity chromatography on W-7 agarose of the crude fractions from mammary gland and brain yielded pure proteins containing one trimethyllysine residue per 16,800 daltons with essentially identical amino acid compositions. Kinetic parameters of these two proteins with respect to their ability to activate phosphodiesterase were determined. The constants for half maximum activation were .39 and .44 nM for bovine brain and bovine mammary gland calmodulins, respectively; both proteins gave similar maximum velocities. Based on the amino acid composition and kinetic data, it is concluded that the two proteins are essentially identical.
...
PMID:Isolation and characterization of bovine mammary calmodulin. 366 28

A protein that resembles vertebrate calmodulins and troponin C has been isolated from Chlamydomonas flagella by using a calmodulin purification protocol that included calcium-dependent affinity-based adsorption chromatography on phenothiazine-Sepharose conjugates. The flagellar protein resembled calmodulin in elution from reverse-phase columns, had a peptide map similar to that of calmodulin, and competed with vertebrate calmodulin in a radioimmunoassay using antisera against vertebrate calmodulin. However, this flagellar protein did not activate phosphodiesterase, lacked N epsilon-trimethyllysine, and had an isoelectric point approximately 0.3 pH unit higher than that of vertebrate calmodulin. When analyzed by polyacrylamide gel electrophoresis under various conditions, the Chlamydomonas protein migrated between vertebrate calmodulins and rabbit skeletal muscle troponin C and did not manifest a large calcium-dependent mobility shift. This calmodulin-like protein was identified as one of the approximately 200 35S-labeled components in Chlamydomonas flagella resolved by two-dimensional gel electrophoresis. These studies indicate that calmodulin and a structurally and functionally homologous protein are present in the same cell. These studies also demonstrate that caution is necessary: (i) in identifying a protein as a calmodulin, (ii) in using phenothiazines or antisera directed against vertebrate calmodulins as specific probes for calmodulin, and (iii) in the interpretation of experiments on biological systems in which calmodulin is substituted for the homologous calmodulin-like protein.
...
PMID:Similarities and dissimilarities between calmodulin and a Chlamydomonas flagellar protein. 625 39

A protein isolated from Limulus polyphemus amoebocyte activates the hydrolysis of cyclic AMP by phosphodiesterase. The protein activator, like calmodulin, requires Ca2+ for its activity and is antagonized by calmodulin-modulating protein from bovine brain. 2-Chloro-10-(3-aminopropyl)-phenothiazine, a compound known to bind calmodulin, also inhibits the effect of the protein activator. This Limulus protein activator is an acidic protein with high percentage of glutamate and aspartate; it contains trimethyllysine, a characteristic amino acid found in all calmodulin. It is different from calmodulin isolated from other species, however, in its molecular weight (4 to 5 times greater), amino acid composition, antigenicity, and binding ability on 2-chloro-10-(3-aminopropyl)-phenothiazine affinity column chromatography. The amino acid composition, gel electrophoresis pattern, and molecular weight of this protein activator are indistinguishable from endotoxin-binding protein which we isolated previously by other independent methods. Immunologic studies demonstrate that these two proteins are essentially identical. The endotoxin-binding protein thus has the dual functions of binding endotoxin, and showing calmodulin-like activity. It may play an important role in degranulation of Limulus amoebocytes which is induced by minute amounts of gram-negative bacterial endotoxin.
...
PMID:Studies on Limulus amoebocyte. Isolation and identification of a membrane-bound protein activator of cyclic nucleotide phosphodiesterase from Limulus amoebocyte. 626 11

Extruded trichocysts are composed of a family of proteins with molecular weights between 15,000 and 20,000. We have used heat treatment and affinity chromatography on fluphenazine-Sepharose to purify calmodulinlike proteins from whole cells and from extruded trichocysts. The purified protein from trichocysts is indistinguishable from that of whole cells; it is heat-stable, activates brain phosphodiesterase in a Ca++-dependent fashion, changes mobility on SDS polyacrylamide gels in the presence of Ca++, contains 1 mol of trimethyllysine/17 kdaltons, and has the amino acid composition characteristic of calmodulins. Calmodulin is a major component of purified, extruded trichocysts, of which it represents between 1 and 10% by mass. The other proteins of the trichocyst also resemble calmodulin in several properties. Possible roles for calmodulin in the Ca++-activated extrusion of trichocysts is discussed.
...
PMID:Calmodulin is a major component of extruded trichocysts from Paramecium tetraurelia. 627 12

Calmodulin, a calcium-binding protein with no known enzymatic activity but multiple, in vitro effector activities, has been purified to apparent homogeneity from the unicellular green alga Chlamydomonas reinhardtii and compared to calmodulin from vertebrates and higher plants. Chlamydomonas calmodulin was characterized in terms of electrophoretic mobility, amino acid composition, limited amino acid sequence analysis, immunoreactivity, and phosphodiesterase activation. Chlamydomonas calmodulin has two histidine residues similar to calmodulin from the protozoan Tetrahymena. However, unlike the protozoan calmodulin, only one of the histidinyl residues of Chlamydomonas calmodulin is found in the COOH-terminal third of the molecule. Chlamydomonas calmodulin lacks trimethyllysine but does have a lysine residue at the amino acid sequence position corresponding to the trimethyllysine residue in bovine brain and spinach calmodulins. The lack of this post-translational modification does not prevent Chlamydomonas calmodulin from quantitatively activating bovine brain phosphodiesterase. These studies also demonstrate that this unique calmodulin from a phylogenetically earlier eukaryote may be as similar to vertebrate calmodulin as it is to higher plant calmodulins, and suggest that Chlamydomonas calmodulin may more closely approximate the characteristics of a putative precursor of the calmodulin family than any calmodulin characterized to date.
...
PMID:Isolation and characterization of calmodulin from the motile green alga Chlamydomonas reinhardtii. 632 90

A novel Ca2+-binding protein (CBP-18) has been identified and purified from bovine brain. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified protein consists of a single band of apparent Mr 18,000 in the presence of Ca2+ or 20,000 in the presence of EGTA. CBP-18 contains one high affinity Ca2+-binding site, measured at 10(-5) M Ca2+ in the presence of 1 mM Mg2+ and 0.1 M K+. The amino acid composition and UV absorption spectrum distinguish CBP-18 from other Ca2+-binding proteins identified in brain. The protein has an extinction coefficient epsilon 1% 279 nm = 4.9 and contains 1 tryptophan/mol, 5 tyrosines/mol, and no trimethyllysine. CBP-18 does not interact with or activate calmodulin-stimulated phosphodiesterase. However, available evidence suggests that CBP-18 binds to other component(s) present in the brain extract in a Ca2+-dependent manner.
...
PMID:Purification and characterization of a novel Ca2+-binding protein (CBP-18) from bovine brain. 669 52

Calmodulin has been isolated and characterized from the gill of the bay scallop aequipecten irradians. Quantitative electrophoretic analysis of epithelial cell fractions show most of the calmodulin to be localized in the cilia, specifically in the detergent- solubilized membrane-matrix fraction. Calmodulin represents 2.2 +/- 0.3 percent of the membrane-matrix protein or 0.41 +/- 0.5 percent of the total ciliary protein. Its concentration is at least 10(-4) M if distributed uniformly within the matrix. Extraction in the presence of calcium suggests that the calmodulin is not bound to the axoneme proper. The ciliary protein is identified as a calmodulin on the basis of its calcium- dependent binding to a fluphenazine-sepharose affinity column and its comigration with bovine brain calmodulin on alkaline-urea and SDS polyacrylamide gels in both the presence and absence of calcium. Scallop ciliary calmodulin activates bovine brain phosphodiesterase to the same extent as bovine brain and chicken gizzard calmodulins. Containing trimethyllysine and lacking cysteine and tryptophan, the amino acid composition of gill calmodulin is typical of known calmodulins, except that it is relatively high in serine and low in methionine. Its composition is less acidic than other calmodulins, in agreement with an observed isoelectric point approximately 0.2 units higher than that of bovine brain. Comparative tryptic peptide mapping of scallop gill ciliary and bovine brain calmodulins indicates coincidence of over 75 percent of the major peptides, but at least two major peptides in each show no near-equivalency. Preliminary results using ATP-reactivated gill cell models show no effect of calcium at micromolar levels on ciliary beat or directionality of the lateral cilia, the cilia which constitute the vast majority of those isolated. However, ciliary arrest will occur at calcium levels more than 150 muM. Because calmodulin usually functions in the micromolar range, its role in this system is unclear. Scallop gill ciliary calmodulin may be involved in the direct regulation of dyneintubule sliding, or it may serve some coupled calcium transport function. At the concentration in which it is found, it must also at least act as a calcium buffer.
...
PMID:Specific localization of scallop gill epithelial calmodulin in cilia. 708 52

Calmodulin was isolated as an electrophoretically homogeneous protein from bovine posterior pituitary glands. The yield indicated that this gland is a particularly rich source. Purified bovine posterior pituitary calmodulin and bovine brain calmodulin had identical electrophoretic mobilities on 10% and 12% polyacrylamide gels. The protein was further identified by molecular weight determination and by amino acid analysis which showed that it contained trimethyllysine, one residue per molecule. Bovine posterior pituitary calmodulin was found to activate a preparation of calmodulin-deficient phosphodiesterase from bovine heart. In addition, pituitary calmodulin stimulated Ca+ + Mg2+-ATPase activity associated with a purified nerve ending plasma membrane fraction. This dependence could only be demonstrated after successive washing of the membranes with EGTA buffers, a procedure designed to remove endogenous calmodulin.
...
PMID:Purification and characterization of posterior pituitary calmodulin and its activation of neurosecretosome Ca2+ + Mg2+-ATPase activities. 711 92


1 2 Next >>

---