• The Korean Journal of Physiology and Pharmacology
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• v.12 no.3
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• pp.95-99
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• 2008

Calcium ($Ca^{2+}$) is an intracellular second messenger associated with neuronal plasticity of the central nervous system. The calcium-binding proteins regulate the $Ca^{2+}$-mediated signals in the cytoplasm and buffer the calcium concentration. This study examined temporal changes of three calcium-binding proteins (calretinin, calbindin and parvalbumin) in the medial vestibular nucleus (MVN) during vestibular compensation after unilateral labyrinthectomy (UL) in rats. Rats underwent UL, and the changes in the expression of these proteins at 2, 6, 12, 24, 48, and 72 h were examined by immuno-fluorescence staining. The expression levels of all three proteins increased immediately after UL and returned to the control level by 48 h. However, the level of calretinin showed changes different from the other two proteins, being expressed at significantly higher level in the contralateral MVN than in the ipsilateral MVN 2 h after UL, whereas the other two proteins showed similar expression levels in both the ipsilateral and contralateral MVN. These results suggest that the calcium binding proteins have some protective activity against the increased $Ca^{2+}$ levels in the MVN. In particular, calretinin might be more responsive to neuronal activity than calbindin or parvalbumin.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.231-235
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• 2009

Objective : While many factors contribute to aging, changes in calcium homeostasis and calcium related neuronal processes are likely to be important. High intracellular calcium is toxic to cells and alterations in calcium homeostasis are associated with changes in calcium-binding proteins, which confine free $Ca^{2+}$. We therefore assayed the expression of the calcium binding proteins calretinin and calbindin in the central auditory nervous system of rats. Methods : Using antibodies to calretinin and calbindin, we assayed their expression in the cochlear nucleus, superior olivary nucleus, inferior colliculus, medial geniculate body and auditory cortex of young (4 months old) and aged (24 months old) rats. Results : Calretinin and calbindin staining intensity in neurons of the cochlear nucleus was significantly higher in aged than in young rats (p<0.05) The number and staining intensity of calretinin-positive neurons in the inferior colliculus, and of calbindin-positive neurons in the superior olivary nucleus were greater in aged than in young rats (p<0.05). Conclusion : These results suggest that auditory processing is altered during aging, which may be due to increased intracellular $Ca^{2+}$ concentration, consequently leading to increased immunoreactivity toward calcium-binding proteins.

• Journal of Microbiology
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• v.37 no.1
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• pp.21-26
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• 1999

Two novel calcium-binding proteins, named CAB-I and CAB-II, have been isolated from Streptomyces coelicolor. Purification of the calcium-binding proteins involved heat treatment, fractionation with ammonium sulfate, acid treatment, anion exchange and hydrophobic interaction column chromatography, FPLC gel filtration, and preparative isoelectric focusing. A chelex competitive assay and 45Ca autoradiography verified the calcium-binding ability of the proteins. The major band CAB-II has an apparent molecular weight of 26,000 determined by SDS-polyacrylamide gel electrophoresis and 340,000 determined by gel filtration. The isoelectric point of this molecule showed the acidic nature of the molecule. N-terminal amino acid sequence analysis shows homology to rat Ca2+/calmodulin-dependent protein kinase-II (CAB-II) and yeast phosphoprotein phosphatase (CAB-I).

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.43-43
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• 2001

In cells of the eukaryotic microorganism Dictyostelium discoideum, at least eight small, four-EF hand calcium-binding proteins respectively are expressed at specific stages during development. One of these proteins, calcium-binding protein 3 (CBP3), first appears just prior to cell aggregation and then maintains relatively constant levels throughout development.(omitted)

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.607-611
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• 2004

Glycinin, one of the predominant storage proteins in soybeans, was examined as to whether it could be used as a calcium-binding mediator after chemical phosphorylation and enzymatic hydrolysis. Glycinin is composed of six subunits. One of the proglycinin subunits $(A_{la}B_{lb})$ was overexpressed in E. coli to obtain nonphosphorylated proteins with homogeneity. To investigate the enhanced calcium-binding properties of the phosphopeptides, the proglycinin was purified, phosphorylated, and hydrolyzed with trypsin. The proglycinin expressed in E. coli was purified by ammonium sulfate precipitation, ion-exchange chromatography, and cryoprecipitation. Chemical phosphorylation by sodium trimetaphosphate was performed to obtain phosphorylated proglycinin. After the phosphorylation, one-dimensional isoelectric focusing gel electroanalysis confirmed the phosphorylation of the proglycinin. The phosphorylated peptides were then hydrolyzed with trypsin, followed by a binding reaction with calcium chloride. The calcium-bound phosphopeptides were finally separated using immobilized metal $(Ca^{2+})$ chromatography. Consequently, a limited tryptic hydrolysate of the isolated phosphopeptides exhibited an enhanced calcium-binding ability, suggesting the potential of glycinin phosphopeptides as a calcium-binding mediator with greater availability.

• Molecules and Cells
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• v.21 no.1
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• pp.34-41
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• 2006

The neuronal localization of alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionic acid (AMPA) glutamate receptor (GluR) subunits is vital as they play key roles in the regulation of calcium permeability. We have examined the distribution of the calcium permeable AMPA glutamate receptor subunit GluR1 in the mouse visual cortex immunocytochemically. We compared this distribution to that of the calcium-binding proteins calbindin D28K, calretinin, and parvalbumin, and of GABA. The highest density of GluR1-immunoreactive (IR) neurons was found in layers II/III. Enucleation appeared to have no effect on the distribution of GluR1-IR neurons. The labeled neurons varied in morphology; the majority were round or oval and no pyramidal cells were labeled by the antibody. Two-color immunofluorescence revealed that 26.27%, 10.65%, and 40.31% of the GluR1-IR cells also contained, respectively, calbindin D28K, calretinin, and parvalbumin. 20.74% of the GluR1-IR neurons also expressed GABA. These results indicate that many neurons that express calcium-permeable GluR1 also express calcium binding proteins. They also demonstrate that one fifth of the GluR1-IR neurons in the mouse visual cortex are GABAergic interneurons.

• Genomics & Informatics
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• v.15 no.4
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• pp.162-169
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• 2017

Metal binding proteins or metallo-proteins are important for the stability of the protein and also serve as co-factors in various functions like controlling metabolism, regulating signal transport, and metal homeostasis. In structural genomics, prediction of metal binding proteins help in the selection of suitable growth medium for overexpression's studies and also help in obtaining the functional protein. Computational prediction using machine learning approach has been widely used in various fields of bioinformatics based on the fact all the information contains in amino acid sequence. In this study, random forest machine learning prediction systems were deployed with simplified amino acid for prediction of individual major metal ion binding sites like copper, calcium, cobalt, iron, magnesium, manganese, nickel, and zinc.

• Food Science and Preservation
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• v.19 no.3
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• pp.438-442
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• 2012

To prepare calcium-binding peptides as calcium supplement, barley proteins were hydrolyzed using Flavourzyme for 18 h and the hydrolysates were ultra-filtered under 3 kDa as a molecular weight. The resultant filtered peptides were fractionated using ion exchange and normal-phase high performance liquid chromatography. Then each fraction that was obtained was determined for its calcium-binding activity to isolate the calcium-binding peptides. As a result, the highest calcium-binding peptide fraction was obtained, and the results suggest that barley protein hydrolysates can be used as a calcium supplement.

• Parasites, Hosts and Diseases
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• v.56 no.1
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• pp.81-86
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• 2018

Four isoforms of calcium binding proteins containing 2 EF hand motifs and a dynein light chain-like domain in the human liver fluke Opisthorchis viverrini, namely OvCaBP1, 2, 3, and 4, were characterized. They had molecular weights of 22.7, 21.6, 23.7, and 22.5 kDa, respectively and showed 37.2-42.1% sequence identity to CaBP22.8 of O. viverrini. All were detected in 2- and 4-week-old immature and mature parasites. Additionally, OvCaBP4 was found in newly excysted juveniles. Polyclonal antibodies against each isoform were generated to detect the native proteins in parasite extracts by Western blot analysis. All OvCaBPs were detected in soluble and insoluble crude worm extracts and in the excretory-secretory product, at approximate sizes of 21-23 kDa. The ion-binding properties of the proteins were analyzed by mobility shift assays with the divalent cations $Ca^{2+}$, $Mg^{2+}$, $Zn^{2+}$, and $Cu^{2+}$. All OvCaBPs showed mobility shifts with $Ca^{2+}$ and $Zn^{2+}$. OvCaBP1 showed also positive results with $Mg^{2+}$ and $Cu^{2+}$. As tegumental proteins, OvCaBP1, 2, and 3 are interesting drug targets for the treatment of opisthorchiasis.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.41-42
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• 1998

The changes in calcium binding protein(CBP) of mouse epididymal sperm during their post-testicular differentiation were analyzed by two-dimensional SDS-PAGE. According to dpididymal maturation, capacitation and acrosome reaction of spermatozoa, both quantitative and qualitative changes of CBPs in the epididymal sperm was detected. It suggested that the development of fertilizing ability of epididymal sperm was closely related to the changes in the CBPs profiles of sperm during epidiyaml transit.