N-acetyl-beta-D-hexosaminidase component A. Different forms in human tissues and fluids

Area of Science:

• Biochemistry
• Enzymology
• Human Physiology

Background:

• Hexosaminidase A is a crucial enzyme found in various human tissues and bodily fluids.
• Previous studies have characterized hexosaminidase A from liver and other tissues, but serum forms require further investigation.

Purpose of the Study:

• To differentiate and characterize the components of human serum hexosaminidase A.
• To investigate the relationship between serum and tissue-derived hexosaminidase A.
• To explore the potential origin of serum hexosaminidase A forms.

Main Methods:

• Enzyme purification and separation using DEAE-cellulose chromatography.
• Size exclusion chromatography (Sephadex G-150) with a multiple-pass technique.
• Enzymatic treatment with Clostridium perfringens neuraminidase.

Main Results:

• Human serum hexosaminidase A resolved into two distinct components: a minor form (similar to liver enzyme) and a major form with different chromatographic properties.
• The major serum form exhibited altered binding to DEAE-cellulose and eluted earlier from Sephadex G-150 compared to the liver form.
• Neuraminidase treatment specifically modified the major serum hexosaminidase A, reducing its affinity for DEAE-cellulose.
• Tear hexosaminidase A resembled the serum form, while tissue, urine, and lymph forms were similar to the liver enzyme.

Conclusions:

• Human serum contains at least two distinct forms of hexosaminidase A.
• The major serum hexosaminidase A component is likely a modified form of the liver enzyme, possibly through glycosylation.
• These findings suggest a potential pathway for the secretion of hexosaminidase A into the bloodstream.