scholarly journals The Influence of Different Classes of Amino Acids on Calcium Phosphates Seeded Growth

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4798
Author(s):  
Tea Mihelj Josipović ◽  
Monika Kovačević ◽  
Sarah Mateša ◽  
Marina Kostešić ◽  
Nives Matijaković ◽  
...  
Keyword(s):  
Amino Acids ◽  
Calcium Phosphate ◽  
Control Systems ◽  
Aspartic Acid ◽  
Significant Influence ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Seeded Growth ◽  
Material Synthesis

Amino acids (AAs) attract attention for elucidating the role of proteins in biomineralization and the preparation of functionalized biomaterials. The influence that AAs exert on calcium phosphate (CaP) mineralization is still not completely understood, as contradictory results have been reported. In this paper, the influence of the addition of different classes of AAs, charged (L-aspartic acid, Asp; L-lysine, Lys), polar (L-asparagine, Asn; L-serine, Ser; L-tyrosine, Tyr), and non-polar (L-phenylalanine, Phe), on CaP growth in the presence of octacalcium phosphate (OCP) and calcium hydrogenphosphate dihydrate (DCPD) seeds was investigated. In control systems (without AAs), a calcium-deficient apatite (CaDHA) layer was formed on the surface of OCP, while a mixture of CaDHA and OCP in the form of spherical aggregates was formed on the surface of DCPD crystals. Charged and non-polar promoted, while polar AAs inhibited CaDHA formation on the OCP seeds. In the case of DCPD, Lys, Asp, and Phe promoted CaP formation, while the influence of other AAs was negligible. The most efficient promotor of precipitation in both cases was non-polar Phe. No significant influence of AAs on the composition and morphology of precipitates was observed. The obtained results are of interest for understanding biomineralization processes and additive controlled material synthesis.

Seeded Growth of Calcium Phosphates: Effect of Different Calcium Phosphate Seed Material

1976 ◽  
Vol 55 (4) ◽  
pp. 617-624 ◽  
Author(s):  
G.H. Nancollas ◽  
J.S. Wefel
Keyword(s):  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Dicalcium Phosphate ◽  
Dicalcium Phosphate Dihydrate ◽  
Seeded Growth ◽  
Seed Crystals ◽  
Phosphate Dihydrate ◽  
Supersaturated Solutions

The growth of calcium phosphates on seed materials, dicalcium PhosPhate dihydrate (DCPD), tricalcium phosphate (TCP), octacalcium phosphate (OCP), and hydroxyapatite (HAP) in stable supersaturated solutions has been studied under conditions of pH and concentration for which the predominant phases are 1, DCPD, and II, HAP. All seed crystals are good nucleators for DCPD in system I, but, aside from HAP itself, only OCP will readily induce growth under condition II.

scholarly journals Enhancement of aromatase activity by D-aspartic acid in the ovary of the lizard Podarcis s. sicula

Reproduction ◽  
2001 ◽  
pp. 803-808 ◽  
Author(s):  
L Assisi ◽  
V Botte ◽  
A D'Aniello ◽  
MM Di Fiore
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Reproductive Cycle ◽  
Catalytic Properties ◽  
Ovarian Tissue ◽  
Experimental Treatment ◽  
Tissue Homogenate ◽  
Aromatase Activity

The present study investigated the role of D-aspartic acid (D-Asp) in ovarian steroidogenesis and its effect on aromatase activity in the lizard, Podarcis s. sicula. It was determined that D-Asp concentrations vary significantly during phases of the reproductive cycle: they vary inversely with testosterone concentrations and directly with oestradiol concentrations in the ovary and plasma. Experimental treatment showed that administration of D-Asp induces a decrease in testosterone and an increase in oestradiol, and that treatment with other amino acids (L-Asp, D-Glu and D-Ala) instead of D-Asp has no effects. Experiments in vitro confirmed these results. Furthermore, these experiments showed an increase in aromatase activity, as the addition of D-Asp either to fresh ovarian tissue homogenate or to acetonic powder of ovarian follicles induced a significant increase in the conversion of testosterone to oestradiol. Aromatase activity is four times greater in the presence of D-Asp than in its absence. However, almost equivalent values of the two K(m) values (both approximately 25 nmol l(-1)) indicate that aromatase has the same catalytic properties in both cases.

scholarly journals Role of Aspartic and Polyaspartic Acid on the Synthesis and Hydrolysis of Brushite.

2019 ◽  
Vol 10 (1) ◽  
pp. 11 ◽  
Author(s):  
Katia Rubini ◽  
Elisa Boanini ◽  
Adriana Bigi
Keyword(s):  
Aspartic Acid ◽  
Octacalcium Phosphate ◽  
Physiological Solution ◽  
Cooperative Action ◽  
Phosphate Dihydrate ◽  
Mineral Phases ◽  
Carboxylate Groups ◽  
Hydrolysis Of ◽  
Thermal Stability Of

Dicalcium phosphate dihydrate (DCPD) is one of the mineral phases indicated as possible precursors of biological apatites and it is widely employed in the preparation of calcium phosphate bone cements. Herein, we investigated the possibility to functionalize DCPD with aspartic acid (ASP) and poly-aspartic acid (PASP), as models of the acidic macromolecules of biomineralized tissues, and studied their influence on DCPD hydrolysis. To this aim, the synthesis of DCPD was performed in aqueous solution in the presence of increasing concentrations of PASP and ASP, whereas the hydrolysis reaction was carried out in physiological solution up to three days. The results indicate that it is possible to prepare DCPD functionalized with PASP up to a polyelectrolyte content of about 2.3 wt%. The increase of PASP content induces crystal aggregation, reduction of the yield of the reaction and of the thermal stability of the synthesized DCPD. Moreover, DCPD samples functionalized with PASP display a slower hydrolysis than pure DCPD. On the other hand, in the explored range of concentrations (up to 10 mM) ASP is not incorporated into DCPD and does not influence its crystallization nor its hydrolysis. At variance, when present in the hydrolysis solution, ASP, and even more PASP, delays the conversion into the more stable phases, octacalcium phosphate and/or hydroxyapatite. The greater influence of PASP on the synthesis and hydrolysis of DCPD can be ascribed to the cooperative action of the carboxylate groups and to its good fit with DCPD structure.

THE ROLE OF KETO ACIDS IN PHOTOSYNTHETIC CARBON DIOXIDE ASSIMILATION

1956 ◽  
Vol 34 (1) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Sugar Beet ◽  
Aspartic Acid ◽  
Pyruvic Acid ◽  
Carbon Dioxide Assimilation ◽  
Free Air ◽  
Keto Acids ◽  
Photosynthetic Carbon

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.

Exploring the role of ions and amino acids in directing the growth of minerals from solution

2008 ◽  
Vol 72 (1) ◽  
pp. 273-276 ◽  
Author(s):  
S. Piana ◽  
F. Jones ◽  
Z. Taylor ◽  
P. Raiteri ◽  
J. D. Gale
Keyword(s):  
Amino Acids ◽  
Computer Simulation ◽  
Free Energy ◽  
Aspartic Acid ◽  
Morphology Control ◽  
New Approach ◽  
Activation Free Energy

AbstractThe influence of both sulphate ions and aspartic acid on directing the growth of baryte has been explored using computer simulation. Both species are found to significantly reduce the activation free-energy to growth under appropriate conditions, with the influence of sulphate being surface specific. This offers the potential for a new approach to morphology control without inhibition that may have implications for biomineralization.

scholarly journals Physico-chemical properties of calcium phosphates

2012 ◽  
Vol 59 (1) ◽  
pp. 7-21 ◽  
Author(s):  
Vesna Babic-Ivancic ◽  
Maja Dutour-Sikiric
Keyword(s):  
Calcium Phosphates ◽  
Chemical Properties ◽  
Organic Matrix ◽  
Octacalcium Phosphate ◽  
Carbonate Apatite ◽  
Organic Additives ◽  
Biologically Relevant ◽  
Beta Tricalcium Phosphate ◽  
Physico Chemical

Calcium phosphates have important role in biological and pathological mineralization. While only one of calcium phosphates, carbonate apatite, represents the main mineral component of teeth and bones, octacalcium phosphate, calcium hydrogenphosphate dihydrate and beta-tricalcium phosphate occur in pathological deposits. From the stand-point of chemists, processes of biological and pathological mineralization could be considered as deposition of inorganic phase within organic matrix, i.e. formation of inorganic-organic composites. Although this approach is very simplified at first glance, it allows clarification of important issues related to biomineralization (e.g. what is the role of individual components of organic matrix in the emerging solid tissue), and design and preparation of new materials for hard tissue regeneration (e.g. process of transformation after implantation). The importance of investigation about calcium phosphates will be presented through the overview of basic physico-chemical reactions related to the formation and transformation of biologically relevant calcium phosphates and their interaction with various organic additives in the laboratory.

THE ROLE OF KETO ACIDS IN PHOTOSYNTHETIC CARBON DIOXIDE ASSIMILATION

1956 ◽  
Vol 34 (3) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Sugar Beet ◽  
Aspartic Acid ◽  
Pyruvic Acid ◽  
Carbon Dioxide Assimilation ◽  
Free Air ◽  
Keto Acids ◽  
Photosynthetic Carbon

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.

The Influence of Fluoride on the Seeded Growth of Apatite From Stable Supersaturated Solutions at pH 7.4

1980 ◽  
Vol 59 (2) ◽  
pp. 144-150 ◽  
Author(s):  
E.D. Eanes
Keyword(s):  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Seeded Growth ◽  
Seed Surface ◽  
Solution Supersaturation ◽  
Comparable Effect ◽  
Stable Solutions ◽  
The Stability ◽  
Phosphate Solutions ◽  
Supersaturated Solutions

Previous studies have shown that fluoride affected the formation of apatite in spontaneous precipitations from unstable calcium phosphate solutions partly through its effect on the stability of such nonapatitic precursors as octacalcium phosphate, Ca 8H2(PO4)6-5H2O. The present study shows that fluoride had a comparable effect on the seeded growth of apatite from stable solutions when the degree of solution supersaturation favored the transient development of octacalcium phosphate precursors on the seed surface.

scholarly journals Phase transformation of calcium phosphates in the presence of glutamic acid

2011 ◽  
Vol 89 (7) ◽  
pp. 885-891 ◽  
Author(s):  
Tim W. T. Tsai ◽  
Wei-Ya Chen ◽  
Yao-Hung Tseng ◽  
Jerry C. C. Chan
Keyword(s):  
Phase Transformation ◽  
Calcium Phosphate ◽  
Glutamic Acid ◽  
Crystal Surface ◽  
Calcium Phosphates ◽  
Water Layer ◽  
Octacalcium Phosphate ◽  
Growth Direction ◽  
Transformation Kinetics ◽  
Transformation Pathway

This work describes a phase-transformation pathway of calcium phosphate in the presence of glutamic acid. The route follows the order starting from amorphous calcium phosphate and brushite, then octacalcium phosphate (OCP), and finally hydroxyapatite (HAp). The preferred growth direction of the intermediate OCP and the final HAp phases lies along the c axis. On the basis of our scanning electron microscopy, X-ray powder diffraction, and 31P solid-state NMR data, we suggest that the transformation is via the dissolution–reprecipitation process, which is facilitated in the presence of glutamic acid. The effect on the transformation kinetics is rationalized by the disruption of the water layer bound on the crystal surface.

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