Related Experiment Videos
A phosphorylated keratohyalin-derived precursor of epidermal stratum corneum basic protein
The Journal of Biological Chemistry
|March 25, 1980
Summary
Researchers purified a precursor to stratum corneum basic protein (SCBP) from epidermal keratohyalin granules. This precursor is similar in amino acid sequence but differs in charge and phosphate content from mature SCBP.
Area of Science:
- Biochemistry
- Dermatology
- Protein Chemistry
Background:
- Stratum corneum basic protein (SCBP) is a cationic protein found in epidermal keratohyalin granules.
- Understanding SCBP's precursor is crucial for elucidating epidermal differentiation and keratinization processes.
Purpose of the Study:
- To purify and characterize the precursor of stratum corneum basic protein (SCBP).
- To compare the biochemical and structural properties of the SCBP precursor with mature SCBP.
Main Methods:
- Purification of the SCBP precursor from epidermal keratohyalin granule extracts.
- Amino acid composition analysis.
- Immunological reactivity testing using antibody to SCBP.
- Peptide mapping using elastase in SDS-polyacrylamide gel electrophoresis.
- Analysis of protein mobility and net charge via SDS-PAGE and pI determination.
Main Results:
- The SCBP precursor was successfully purified.
- Precursor and SCBP share similar amino acid compositions and immunological reactivity.
- Peptide mapping indicates similar primary amino acid sequences.
- Proteins differ in SDS-PAGE mobility and net charge.
- The precursor's lower pI (6.9) is attributed to 15-20 mol of covalently bound phosphate per mol of protein, absent in mature SCBP.
Conclusions:
- The purified protein is the precursor of SCBP.
- Post-translational phosphorylation distinguishes the SCBP precursor from mature SCBP.
- These findings provide insights into the processing and maturation of SCBP during epidermal differentiation.