The DOI matches its Crossref record.
Aspartic acid racemization in tooth enamel from living humans.
Open accessAbstract
The aspartic acid in human tooth enamel shows increasing racemization with age. This increase is not seen in the metabolically active protein hemoglobin. The rate constant for the racemization reaction of aspartic acid in human tooth enamel was found to be 8.29 X 10(-4) yr-1. This rate constant suggests that in any protein with a long in vivo lifetime, D-aspartic acid will accumulate with age (about 8% of total aspartic acid in enamel will be the D-enantiomer after 60 years). Thus, racemization may play some role in the aging process affecting metabolically stable tissues in long-lived homeotherms. Aspartic acid racemization in toogh enamel also provides a biochronological tool for assessing the age of living mammals.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cited by
Geiger, T., & Clarke, S. (1987) · Journal of Biological Chemistry · doi:10.1016/s0021-9258(19)75855-4 · Cited by 1,311
The Search for Chiral Asymmetry as a Potential Biosignature in our Solar System
Glavin, D. P., Burton, A. S., Elsila, J. E., Aponte, J. C., & Dworkin, J. P. (2020) · Chemical Reviews · doi:10.1021/acs.chemrev.9b00474 · Cited by 293
Warinner, C., Korzow Richter, K., & Collins, M. J. (2022) · Chemical Reviews · doi:10.1021/acs.chemrev.1c00703 · Cited by 178
Nagata, Y., Fujiwara, T., Kawaguchi-Nagata, K., Fukumori, Y., & Yamanaka, T. (1998) · Biochimica et Biophysica Acta (BBA) - General Subjects · doi:10.1016/s0304-4165(97)00084-6 · Cited by 76
Empirical evaluation of bone extraction protocols
Cleland, T. P., Voegele, K., & Schweitzer, M. H. (2012) · PLoS ONE · doi:10.1371/journal.pone.0031443 · Cited by 60
Metadata
- Authors
- Helfman, P. M., & Bada, J. L.
- Venue
- Proceedings of the National Academy of Sciences
- Published
- 1975-08
- Volume
- 72
- Issue
- 8
- Pages
- 2891-2894
- ISSN
- 0027-8424 (ISSN-L)
- 1091-6490
- OpenAlex
- W2051613001
- Cited by
- 304
- References
- 0
- FWCI
- 88.93
- Type
- journal article
- Language
- en
- Open access
- green
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
How to cite
Cite CoChat for the checks on this page, and the paper for its own findings.
- This page
- CoChat. (2026). Citation check: Aspartic acid racemization in tooth enamel from living humans. https://app.cochat.ai/papers/10.1073/pnas.72.8.2891
- The paper
- Helfman, P. M., & Bada, J. L. (1975). Aspartic acid racemization in tooth enamel from living humans. Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.72.8.2891
Data sources
Bibliographic data: Semantic Scholar, OpenAlex, Crossref.
Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
