Skin sulfhydryl oxidase. Purification and some properties

Area of Science:

• Biochemistry
• Enzymology
• Dermatology

Background:

• Sulfhydryl-oxidizing enzymes play crucial roles in biological systems.
• Understanding these enzymes is key to various physiological processes.
• The presence and function of such enzymes in skin tissue require further investigation.

Purpose of the Study:

• To discover and purify a sulfhydryl-oxidizing enzyme from rat skin.
• To characterize the enzymatic activity and substrate specificity.
• To determine the enzyme's physical and chemical properties.

Main Methods:

• Purification of the enzyme from young rat skin using a multi-step protocol achieving over 600-fold enrichment.
• Assay of enzymatic activity via dithiothreitol oxidation and ribonuclease A renaturation.
• Determination of molecular weight and isoelectric point.
• Investigation of enzyme inhibition by alkylating reagents after preincubation with various thiols.

Main Results:

• A sulfhydryl oxidase was successfully purified from rat skin.
• The enzyme efficiently oxidized various thiols including dithiothreitol, dithioerythritol, D-penicillamine, and L-cysteine.
• It demonstrated the ability to reactivate reductively denatured ribonuclease A.
• Enzyme activity was inhibited by alkylating reagents, particularly after preincubation with substrate thiols.
• Estimated molecular weight: 66,000 +/- 2000 Da; isoelectric point: pH 4.65.

Conclusions:

• A novel sulfhydryl oxidase exists in rat skin with significant thiol-oxidizing capabilities.
• The enzyme's ability to renature denatured ribonuclease A suggests a role in protein folding or repair.
• Characterization provides a foundation for further studies on its physiological role in skin.