Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calmodulin is the name proposed for a multifunctional, calcium binding protein whose presence has been detected in a number of eukaryotic cells. In the studies summarized here, calmodulin has been isolated from spinach leaves (Spinacea oleracea), characterized, and compared to vertebrate calmodulins. Quantitative recovery data for a rapid-isolation protocol demonstrate that calmodulin is a major constituent of spinach leaves. Spinach calmodulin is indistinguishable from vertebrate calmodulins in phosphodiesterase activator activity using vertebrate brain phosphodiesterase and in quantitative immunoreactivity using antiserum made against vertebrate calmodulin. However, spinach calmodulin is really distinguished from vertebrate and invertebrate calmodulins in electrophoretic mobility and in amino acid composition. Spinach calmodulin, like vertebrate calmodulins, lacks tryptophan and contains 1 mol each of N epsilon-trimethyllysine and histidine per 17000 g of protein. In contrast to vertebrate calmodulins, spinach calmodulin has only one tyrosinyl residue and has a threonine/serine ratio of 1.3. While amino acid compositions indicate differences between spinach and vertebrate calmodulins, isolation and characterization of tryptic peptides containing the single histidinyl and N epsilon-trimethyllysyl residues and both prolinyl residues indicate that these regions in spinach calmodulin are similar to the corresponding regions in vertebrate calmodulin. These studies more fully define the general and specific characteristics of calmodulins and indicate that calmodulin structure is not as highly conserved among all eukaryotes as it is among vertebrates and invertebrates.
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PMID:Spinach calmodulin: isolation, characterization, and comparison with vertebrate calmodulins. 745 43

Calmodulin from Drosophila heads has been purified to apparent electrophoretic homogeneity. It has the same characteristics as bovine brain calmodulin with respect to the migration upon polyacrylamide gel electrophoresis and maximal activation of a calmodulin-deficient cAMP phosphodiesterase. The amino acid composition resembles bovine brain calmodulin with the exception that trimethyllysine is absent and that it contains only one tyrosine. The tryptic peptide map of Drosophila calmodulin suggests some differences in the amino acid sequence as compared to bovine brain calmodulin. These proposed differences in the primary structure may explain why Drosophila calmodulin is less potent than bovine brain calmodulin in the activation of a cAMP phosphodiesterase from bovine brain.
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PMID:Characterisation of calmodulin from Drosophila heads. 1100 94

Calmodulin, a multifunctional calcium-modulated protein, has been isolated from spinach leaf tissue and from spinach leaf messenger RNA translation products. The translation protein and the spinach leaf protein have been partially characterized and compared to vertebrate calmodulins. Spinach leaf calmodulin will quantitatively activate bovine brain phosphodiesterase and will undergo a calcium-dependent shift in electrophoretic mobility similar to that of bovine brain calmodulin. In the presence of Ca(2+) the spinach and brain proteins comigrate, but in the presence of chelators they do not. A polyadenylylated RNA fraction has been isolated from spinach leaf tissue and translated in a wheat germ cell-free translation system. The calmodulin synthesized in vitro has been isolated by using calcium-dependent affinity chromatography on phenothiazine-Sepharose conjugates. The translation protein comigrates with spinach calmodulin during polyacrylamide gel electrophoresis whether in the presence or the absence of Ca(2+). The translation protein also undergoes a calcium-dependent mobility shift identical to that of spinach calmodulin. Amino acid analysis of the translation calmodulin indicates that it does not contain N(epsilon)-trimethyllysine, an amino acid residue that is characteristic of all calmodulins previously examined. These studies suggest that N(epsilon)-trimethyllysine is not required for the calcium-dependent interaction of calmodulin with phenothiazines and indicate the potential utility of phenothiazine-Sepharose conjugates as affinity-based adsorbents in biological and biochemical investigations.
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PMID:Isolation and characterization of calmodulin from spinach leaves and in vitro translation mixtures. 1659 1

An amino acid sequence for a Chlamydomonas calmodulin has been elucidated with emphasis on the characterization of differences that are unique to Chlamydomonas and Dictyostelium calmodulin. While the concentration of calmodulin required for half-maximal activation of plant NAD kinase varies among vertebrate, higher plant, algal, and slime mold calmodulins, only calmodulins from the unicellular alga Chlamydomonas and the slime mold Dictyostelium show increased maximal activation of NAD kinase (Roberts, Burgess, Watterson 1984 Plant Physiol 75: 796-798; Marshak, Clarke, Roberts, Watterson 1984 Biochemistry 23: 2891-2899). The same preparations of calmodulin do not show major differences in phosphodiesterase or myosin light chain kinase activator activity.We report here that a Chlamydomonas calmodulin has four primary structural features similar to Dictyostelium that are not found in other calmodulins characterized to date: an altered carboxy terminus including a novel 11-residue extension for Chlamydomonas calmodulin, unique residues at positions 81 and 118, and an unmethylated lysine at position 115. The only amino acid sequence identity unique to Chlamydomonas and Dictyostelium calmodulin is the presence of a lysine at position 115 instead of a trimethyllysine. These studies indicate that the methylation state of lysine 115 may be important in the maximal NAD kinase activator activity of calmodulin and support the concept that calmodulin has multiple functional domains in addition to multiple structural domains.
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PMID:Amino Acid sequence of a novel calmodulin from the unicellular alga chlamydomonas. 1666 69

Calmodulins (CaM) were isolated and characterized from two well-known latex producing plants, Papaver somniferum and Euphorbia lathyris. The molecular weights of both were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 17,000 comparable to that of bovine brain CaM. Amino acid compositions also compared similarly with those of known CaMs, with regard to the presence of trimethyllysine and the ratio of phenylalanine to tyrosine. The Cornish-Bowden equation (SDeltan) revealed strong statistical correlations of P. somniferum and E. lathyris CaM with those of other plants and animals, although their amino acid compositions were not identical. Both plant CaM stimulated CaM dependent cAMP phosphodiesterase: for Papaver somniferum the K(a) was found to be 1.09 nanomolar and for Euphorbia lathyris, 2.01 nanomolar.
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PMID:Purification and Characterization of Calmodulins from Papaver somniferum and Euphorbia lathyris. 1666 73


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