Human body fluid ribonucleases: detection, interrelationships and significance

Area of Science:

• Biochemistry
• Molecular Biology
• Human Physiology

Background:

• Ribonucleases (RNases) are enzymes crucial for RNA metabolism.
• Understanding RNase origins and characteristics in human body fluids is essential for biological and medical research.
• Previous studies faced challenges in RNase detection due to contaminants in Sodium dodecyl sulfate (SDS) preparations.

Purpose of the Study:

• To characterize RNase activities in human serum, urine, and cerebrospinal fluid (CSF).
• To identify the cellular origins of these RNase activities.
• To evaluate the diagnostic utility of plasma RNase levels in malignant diseases.

Main Methods:

• Activity staining following SDS-polyacrylamide gel electrophoresis (PAGE).
• Pre-electrophoresis gel washing with 25% isopropanol to remove SDS contaminants.
• Characterization of RNase bands from serum, urine, and CSF.

Main Results:

• A method was developed to overcome SDS contaminants for effective RNase activity staining.
• RNases in urine (bands A-C) and CSF (bands 1-3) were identified as glycoproteins.
• Leukocytes were identified as the source of urine band D RNase and minor RNase activities in serum and CSF.
• Major serum (RNases 1-5) and urine (band A) RNases do not originate from the pancreas.

Conclusions:

• The study provides a detailed characterization of human body fluid RNases and their cellular origins.
• Elevated plasma RNase levels are unlikely to be specific diagnostic indicators for most cancers.
• Observed increases in plasma RNase may be secondary to factors like advanced age, negative nitrogen balance, or kidney dysfunction.