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Characterization and localization of bovine epidermal transglutaminase substrate
The Journal of Investigative Dermatology
|February 1, 1982
Summary
This study identifies epidermal transglutaminase substrate as a globular, amorphous protein rich in citrulline. It is synthesized in keratinizing cells and located in the cell membrane.
Area of Science:
- Biochemistry
- Cell Biology
- Dermatology
Background:
- Epidermal transglutaminase plays a crucial role in skin structure and barrier function.
- Understanding its substrate is key to elucidating keratinization processes.
Purpose of the Study:
- To purify and characterize the epidermal transglutaminase substrate.
- To determine its molecular properties, amino acid composition, and cellular localization.
Main Methods:
- DEAE-Sepharose CL-6B ion exchange chromatography, Pevikon block electrophoresis, ACA-54 gel filtration.
- Amino acid analysis, sedimentation equilibrium, Ouchterlony double diffusion, indirect immunofluorescence.
Main Results:
- Purified substrate (19% yield) showed high lysine/glutamic acid, low cystine/methionine, and significant citrulline.
- Molecular weight determined as 36,780 ± 350 Da; amorphous, globular aggregates observed.
- Immunologically identical to crosslinked forms; localized in granular and stratum corneum cell membranes.
Conclusions:
- Epidermal transglutaminase substrate is a citrulline-containing protein synthesized in the cytosol.
- It localizes to the cell membrane of keratinizing epidermal cells.