Sorbitol dehydrogenase is a zinc enzyme

Area of Science:

• Biochemistry
• Enzymology
• Metalloprotein studies

Background:

• Sorbitol dehydrogenase (SDH) is an enzyme involved in polyol metabolism.
• Structurally related alcohol dehydrogenases (ADHs) can have multiple zinc atoms per subunit, complicating functional analysis.
• Understanding the role of zinc in enzyme active sites is crucial for biochemistry.

Purpose of the Study:

• To characterize the zinc content of sheep liver sorbitol dehydrogenase.
• To investigate the potential of SDH as a model enzyme for studying zinc function in dehydrogenases.
• To correlate the structure and function of zinc in SDH with other zinc-containing proteins.

Main Methods:

• Enzyme purification from sheep liver.
• Metal content analysis (e.g., atomic absorption spectroscopy).
• Enzyme kinetics and activity assays.

Main Results:

• Tetrameric sheep liver sorbitol dehydrogenase contains one zinc atom per subunit.
• The zinc atom is predominantly located at the enzyme's active site.
• No other specifically bound zinc or iron atoms were detected.

Conclusions:

• Sheep liver sorbitol dehydrogenase serves as a valuable model for studying the precise roles of zinc in polyol and alcohol dehydrogenases.
• The defined zinc stoichiometry simplifies investigations into structure-function relationships in metalloenzymes.
• This finding aids in understanding zinc's role in related enzyme families.