Long-lived metabolic enzymes in the crystalline lens identified by pulse-labeling of mice and mass spectrometry

Pan Liu, Seby Louis Edassery, Laith Ali, Benjamin R. Thomson, Jeffrey N. Savas*, Jing Jin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The lenticular fiber cells are comprised of extremely long-lived proteins while still maintaining an active biochemical state. Dysregulation of these activities has been implicated in diseases such as age-related cataracts. However, the lenticular protein dynamics underlying health and disease is unclear. We sought to measure the global protein turnover rates in the eye using nitrogen-15 labeling of mice and mass spectrometry. We measured the14N/15N-peptide ratios of 248 lens proteins, including Crystallin, Aquaporin, Collagen and enzymes that catalyze glycolysis and oxidation/reduction reactions. Direct comparison of lens cortex versus nucleus revealed little or no15N-protein contents in most nuclear proteins, while there were a broad range of14N/15N ratios in cortex proteins. Unexpectedly, like Crystallins, many enzymes with relatively high abundance in nucleus were also exceedingly long-lived. The slow replacement of these enzymes in spite of young age of mice suggests their potential roles in age-related metabolic changes in the lens.

Original languageEnglish (US)
Article numbere50170
StatePublished - Dec 2019

ASJC Scopus subject areas

  • General Immunology and Microbiology
  • General Biochemistry, Genetics and Molecular Biology
  • General Neuroscience


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