Evaluation of Calcium Binding Capacity of Chelating Agents in Calcium Carbonate Suspension and Effects on Calcium Distribution of Calcium Chelating Agents

In this study, soybean peptides (10-30kDa) with high calcium binding capacity were prepared by enzymatic hydrolysis and ultrafiltration. The results of cell experiments showed that the peptide could transport calcium...

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Novel Peptide with Specific Calcium-Binding Capacity from Schizochytrium sp. Protein Hydrolysates and Calcium Bioavailability in Caco-2 Cells

Marine Drugs ◽

10.3390/md15010003 ◽

2016 ◽

Vol 15 (1) ◽

pp. 3 ◽

Cited By ~ 19

Author(s):

Xixi Cai ◽

Jiaping Lin ◽

Shaoyun Wang

Keyword(s):

Calcium Binding ◽

Binding Capacity ◽

Protein Hydrolysates ◽

Calcium Bioavailability

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Acclimation to hard or soft water at weakly alkaline pH influences gill permeability and gill surface calcium binding in rainbow trout (Oncorhynchus mykiss)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-848 ◽

1995 ◽

Vol 52 (12) ◽

pp. 2583-2593 ◽

Cited By ~ 10

Author(s):

Deke T. Gundersen ◽

Lawrence R. Curtis

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Calcium Binding ◽

Binding Capacity ◽

High Hardness ◽

Alkaline Ph ◽

Surface Binding ◽

Weakly Alkaline ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Osmotic Water

Rainbow trout (Oncorhynchus mykiss) were acclimated for 10 d to soft (0.1 mM as CaCO3) or hard (1.0 mM as CaCO3) water at weakly alkaline pH (8.06–8.34). Following acclimation, individual gill arches were removed for examining the effects of low hardness or high hardness acclimation on gill water permeability, gill Ca2+ interactions, and gill aluminum interactions. Isolated gill arches were exposed to water of varying Ca2+ (0.0–1.0 mM) and aluminum (3.7–37 μM) concentration for osmotic permeability experiments. High hardness acclimated gills had significantly greater percent weight gain over time caused by osmotic water entry than low hardness acclimated gills, when exposed to distilled water (32.34 ± 1.15 and 24.86 ± 0.62%, respectively, after 60-min incubations); these differences were absent when Ca2+ (0.1–1.0 mM) was added to the incubation medium. Gill arch Ca2+ binding experiments resolved two gill surface binding site populations, which differed in their Ca2+ binding affinity. The higher affinity sites were probably associated with gill membrane permeability, because low hardness acclimated gills had more such sites (binding capacity, 0.322 ± 0.027 μmol Ca2+∙g−1) and less permeable gills than high hardness acclimated gills (binding capacity, 0.198 ± 0.004 μmol Ca2+∙g−1). Aluminum had little influence on gill permeability and gill Ca2+ binding.

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Activity-Related Calcium Dynamics in Motoneurons of the Nucleus Hypoglossus From Mouse

Journal of Neurophysiology ◽

10.1152/jn.1999.82.6.2936 ◽

1999 ◽

Vol 82 (6) ◽

pp. 2936-2946 ◽

Cited By ~ 33

Author(s):

Mario B. Lips ◽

Bernhard U. Keller

Keyword(s):

Quantitative Analysis ◽

Action Potential ◽

Calcium Binding ◽

Calcium Influx ◽

Binding Capacity ◽

Calcium Transients ◽

Calcium Dynamics ◽

The Brain

A quantitative analysis of activity-related calcium dynamics was performed in motoneurons of the nucleus hypoglossus in the brain stem slice preparation from mouse by simultaneous patch-clamp and microfluorometric calcium measurements. Motoneurons were analyzed under in vitro conditions that kept them in a functionally intact state represented by rhythmic, inspiratory-related bursts of excitatory postsynaptic currents and associated action potential discharges. Bursts of electrical activity were paralleled by somatic calcium transients resulting from calcium influx through voltage-activated calcium channels, where each action potential accounted for a calcium-mediated charge influx around 2 pC into the somatic compartment. Under in vivo conditions, rhythmic-respiratory activity in young mice occurred at frequencies up to 5 Hz, demonstrating the necessity for rapid calcium elevation and recovery in respiratory-related neurons. The quantitative analysis of hypoglossal calcium homeostasis identified an average extrusion rate, but an exceptionally low endogenous calcium binding capacity as cellular parameters accounting for rapid calcium signaling. Our results suggest that dynamics of somatic calcium transients 1) define an upper limit for the maximum frequency of respiratory-related burst discharges and 2) represent a potentially dangerous determinant of intracellular calcium profiles during pathophysiological and/or excitotoxic conditions.

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Properties and Mutation Analysis of the CelK Cellulose-Binding Domain from the Clostridium thermocellum Cellulosome

Journal of Bacteriology ◽

10.1128/jb.183.5.1552-1559.2001 ◽

2001 ◽

Vol 183 (5) ◽

pp. 1552-1559 ◽

Cited By ~ 21

Author(s):

Irina A. Kataeva ◽

Ronald D. Seidel ◽

Xin-Liang Li ◽

Lars G. Ljungdahl

Keyword(s):

Amino Acids ◽

Calcium Binding ◽

Clostridium Thermocellum ◽

Binding Capacity ◽

Binding Domain ◽

Cellulose Binding Domain ◽

Calcium Binding Site ◽

Aromatic Residues ◽

Cellulose Binding ◽

Family Iv

ABSTRACT The family IV cellulose-binding domain of Clostridium thermocellum CelK (CBDCelK) was expressed inEscherichia coli and purified. It binds to acid-swollen cellulose (ASC) and bacterial microcrystalline cellulose (BMCC) with capacities of 16.03 and 3.95 μmol/g of cellulose and relative affinities (K r) of 2.33 and 9.87 liters/g, respectively. The CBDCelK is the first representative of family IV CBDs to exhibit an affinity for BMCC. The CBDCelKalso binds to the soluble polysaccharides lichenin, glucomannan, and barley β-glucan, which are substrates for CelK. It does not bind to xylan, galactomannan, and carboxymethyl cellulose. The CBDCelK contains 1 mol of calcium per mol. The CBDCelK has three thiol groups and one disulfide, reduction of which results in total loss of cellulose-binding ability. To reveal amino acid residues important for biological function of the domain and to investigate the role of calcium in the CBDCelK four highly conserved aromatic residues (Trp56, Trp94, Tyr111, and Tyr136) and Asp192 were mutated into alanines, giving the mutants W56A, W94A, Y111A, Y136A, and D192A. In addition 14 N-terminal amino acids were deleted, giving the CBD-NCelK. The CBD-NCelK and D192A retained binding parameters close to that of the intact CBDCelK, W56A and W94A totally lost the ability to bind to cellulose, Y136A bound to both ASC and BMCC but with significantly reduced binding capacity and K rand Y111A bound weakly to ASC and did not bind to BMCC. Mutations of the aromatic residues in the CBDCelK led to structural changes revealed by studying solubility, circular-dichroism spectra, dimer formation, and aggregation. Calcium content was drastically decreased in D192A. The results suggest that Asp192 is in the calcium-binding site of the CBDCelK and that calcium does not affect binding to cellulose. The 14 amino acids from the N terminus of the CBDCelK are not important for binding. Tyr136, corresponding to Cellulomonas fimi CenC CBDN1Y85, located near the binding cleft, might be involved in the formation of the binding surface, while Y111, W56A, and W94A are essential for the binding process by keeping the CBDCelK correctly folded.

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