scholarly journals Use of AMS 14C Analysis in the Study of Problems in Aspartic Acid Racemization-Deduced Age Estimates on Bone

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 539-546 ◽  
Author(s):  
Paul Ennis ◽  
E A Noltmann ◽  
P E Hare ◽  
P J Slota ◽  
L A Payen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Chemical State ◽  
Fossil Bone ◽  
Aspartic Acid Racemization ◽  
Age Estimates

Major discordances between AMS 14C- and aspartic acid racemization (AAR)-deduced age estimates on bone samples have led to an examination of factors other than time and temperature that can fundamentally influence the degree of racemization observed in fossil bone. Our studies support previous suggestions that for many bone samples the chemical state of amino acids must be routinely considered if AAR-deduced age estimates are to be used to make meaningful chronologic inferences.

Amino Acid Geochemistry of Fossil Bones from the Rancho La Brea Asphalt Deposit, California

1982 ◽  
Vol 18 (2) ◽  
pp. 174-183 ◽  
Author(s):  
Mark A. S. McMenamin ◽  
David J. Blunt ◽  
Keith A. Kvenvolden ◽  
Scott E. Miller ◽  
Leslie F. Marcus ◽  
...  
Keyword(s):  
Amino Acids ◽  
Los Angeles ◽  
Aspartic Acid ◽  
Equivalent Age ◽  
Aspartic Acid Racemization ◽  
Wide Range ◽  
Fossil Bones ◽  
Minimum Age ◽  
Rancho La Brea ◽  
Age Estimates

AbstractLow aspartic acid d:l ratios and modern collagenlike concentration values indicate that amino acids in bones from the Rancho La Brea asphalt deposit, Los Angeles, California are better preserved than amino acids in bones of equivalent age that have not been preserved in asphalt. Amino acids were recovered from 10 Rancho La Brea bone samples which range in age from less than 200 to greater than 36,000 yr. The calibrated rates of aspartic acid racemization range from 2.1 to 5.0 × 10−6yr−1. Although this wide range of rate constants decreases the level of confidence for age estimates, use of the larger rate constant of 5.0 × 10−6yr−1provides minimum age estimates which fit the known stratigraphic and chronologic records of the Rancho La Brea deposits.

scholarly journals Non-Concordance of Radiocarbon and Amino Acid Racemization Deduced Age Estimates on Human Bone

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 647-654 ◽  
Author(s):  
R E Taylor
Keyword(s):  
Amino Acid ◽  
Aspartic Acid ◽  
Human Bone ◽  
Amino Acid Racemization ◽  
Aspartic Acid Racemization ◽  
Order Of Magnitude ◽  
Direct Counting ◽  
Organic Fractions ◽  
Skeletal Samples ◽  
Age Estimates

Radiocarbon determinations, employing both decay and direct counting, were obtained on various organic fractions of four human skeletal samples previously assigned ages ranging from 28,000 to 70,000 years on the basis of their D/L aspartic acid racemization values. In all four cases, the 14C values require an order of magnitude reduction in age.

Fraction dependent variation of aspartic acid racemization age of fossil bone

Nature ◽  
1980 ◽  
Vol 286 (5776) ◽  
pp. 883-884 ◽  
Author(s):  
Shuji Matsu'ura ◽  
Nobuo Ueta
Keyword(s):  
Aspartic Acid ◽  
Fossil Bone ◽  
Aspartic Acid Racemization

Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization

1999 ◽  
Vol 77 (4) ◽  
pp. 571-580 ◽  
Author(s):  
John C George ◽  
Jeffrey Bada ◽  
Judith Zeh ◽  
Laura Scott ◽  
Stephen E Brown ◽  
...  
Keyword(s):  
Aspartic Acid ◽  
Standard Error ◽  
Sexual Maturity ◽  
Delta Method ◽  
Age And Growth ◽  
Eye Lens ◽  
Bowhead Whales ◽  
Aspartic Acid Racemization ◽  
Coefficients Of Variation ◽  
Age Estimates

A total of 48 eye globes were collected and analyzed to estimate ages of bowhead whales using the aspartic acid racemization technique. In this technique, age is estimated based on intrinsic changes in the D and L enantiomeric isomeric forms of aspartic acid in the eye lens nucleus. Age estimates were successful for 42 animals. Racemization rate (kAsp) for aspartic acid was based on data from earlier studies of humans and fin whales; the estimate used was 1.18 10-3/year. The D/L ratio at birth ((D/L)0) was estimated using animals less than or equal to 2 years of age (n = 8), since variability in the D/L measurements is large enough that differences among ages in this range are unmeasurable. The (D/L)0 estimate was 0.0285. Variance of the age estimates was obtained using the delta method. Based on these data, growth appears faster for females than males, and age at sexual maturity (age at length 12-13 m for males and 13-13.5 m for females) occurs at around 25 years of age. Growth slows markedly for both sexes at roughly 40-50 years of age. Four individuals (all males) exceed 100 years of age. Standard error increased with estimated age, but the age estimates had lower coefficients of variation for older animals. Recoveries of traditional whale-hunting tools from five recently harvested whales also suggest life-spans in excess of 100 years of age in some cases.

Aspartic Acid Racemization in Late Wisconsin Lake Ontario Sediments

1978 ◽  
Vol 9 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Roy Allen Schroeder ◽  
Jeffrey L. Bada
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Aspartic Acid ◽  
Lake Ontario ◽  
Lower Section ◽  
Piston Core ◽  
General Applicability ◽  
The Core ◽  
Aspartic Acid Racemization ◽  
Depositional Age

We have determined aspartic acid racemization and [14C] ages in sediment from a 17-m piston core recovered from Lake Ontario. This core represents a depositional record extending back into the Late Wisconsin. Total organic radiocarbon ages of the glaciolacustrine lower section of the core are older than the true depositional age. Hence we suggest that these ages do not represent time elapsed since deposition but rather may be up to several thousand years too old due to mixing with 14C-depleted organic matter and possibly also D-amino acids contained by the glacier and deposited as the glacier receded. Further studies are suggested that might test this hypothesis as well as establish the general applicability of racemization dating to clay sediments.

Enzymatic Synthesis of 15N-L-aspartic Acid Using Recombinant Aspartase from Escherichia Coli K12

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Iulia Lupan ◽  
Sergiu Chira ◽  
Maria Chiriac ◽  
Nicolae Palibroda ◽  
Octavian Popescu
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Enzymatic Synthesis ◽  
Large Scale ◽  
Recombinant Dna ◽  
Industrial Enzymes ◽  
Recombinant Dna Technology ◽  
Bacterial Fermentation ◽  
Natural Protein ◽  
Novel Method

Amino acids are obtained by bacterial fermentation, extraction from natural protein or enzymatic synthesis from specific substrates. With the introduction of recombinant DNA technology, it has become possible to apply more rational approaches to enzymatic synthesis of amino acids. Aspartase (L-aspartate ammonia-lyase) catalyzes the reversible deamination of L-aspartic acid to yield fumaric acid and ammonia. It is one of the most important industrial enzymes used to produce L-aspartic acid on a large scale. Here we described a novel method for [15N] L-aspartic synthesis from fumarate and ammonia (15NH4Cl) using a recombinant aspartase.

Post-proline endopeptidase, further characterization of the enzyme from pig kidneys

1984 ◽  
Vol 49 (8) ◽  
pp. 1846-1853 ◽  
Author(s):  
Karel Hauzer ◽  
Tomislav Barth ◽  
Linda Servítová ◽  
Karel Jošt
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Relative Molecular Mass ◽  
Enzyme Molecule ◽  
Thiol Compounds ◽  
Modified Method ◽  
N Terminus

A post-proline endopeptidase (EC 3.4.21.26) was isolated from pig kidneys using a modified method described earlier. The enzyme was further purified by ion exchange chromatography on DEAE-Sephacel. The final product contained about 95% of post-proline endopeptidase. The enzyme molecule consisted of one peptide chain with a relative molecular mass of 65 600 to 70 000, containing a large proportion of acidic and alifatic amino acids (glutamic acid, aspartic acid and leucine) and the N-terminus was formed by aspartic acid or asparagine. In order to prevent losses of enzyme activity, thiol compounds has to be added.

The potential mechanism of atmospheric new particle formation involving amino acids with multiple functional groups

2021 ◽  
Author(s):  
Jiarong Liu ◽  
Ling Liu ◽  
Hui Rong ◽  
Xiuhui Zhang
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Functional Groups ◽  
Atmospheric Aerosols ◽  
Potential Role ◽  
Particle Formation ◽  
Potential Mechanism ◽  
New Particle Formation

Amino acids are recognized as significant components of atmospheric aerosols. However, its potential role in the atmospheric new particle formation (NPF) is poorly understood, especially aspartic acid (ASP), one of...

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