Human ribonucleases. Quantitation of pancreatic-like enzymes in serum, urine, and organ preparations.

J L Weickmann,D G Glitz

doi:10.1016/s0021-9258(18)34185-1

Abstract

Antibodies against pure human pancreatic ribonuclease (RNase) were used to study ribonuclease levels in human tissues and body fluids. The antibodies completely inhibit the activity of purified RNase as well as ribonuclease activity in crude pancreatic extracts. RNase activity is inhibited by 70-80% in serum and urine, indicating that a significant proportion of the RNases in these preparations are structurally like the pancreatic enzyme. In contrast, inhibition of RNase activities from spleen (8%) and liver (30%) was inefficient suggesting that most of the RNases in these tissues are structurally unlike the pancreatic enzyme. A competitive binding radioimmunoassay (RIA), sensitive in the range of 1-100 ng of RNase, was developed to quantitate the pancreatic like enzymes. The RIA of crude tissue preparations and samples fractionated by gel filtration was compatible with inhibition results. Enzymes structurally like pancreatic RNase could be quantitated despite the presence of other RNase activities. Immunological quantitation of pancreatic like RNases was also found to be much more simple and precise than enzymatic assays comparing RNA and polycytidylate substrates. We suggest the immunological assays will be useful in the quantitation and definition of tissue of origin of RNases in serum of patients with pancreatic carcinoma.

Highlights

Antibodies against pure human pancreatic ribonusciloen-s of Reddi and Holland [4] orsuggest [5, 18] that the ase (RNase) were used to study ribonuclease levels in increase in the serum RNase of patients with malignant human tissues andbody fluids
We suggest the immunologicalassays will be useful in tation of specific RNase proteins, could be more precise and the quantitation and definition of tissue of origin of more readily adapted for routine use
We describe the crossreactivity of antibodies to the purified RNase with components of various human tissues, serum, and urine and show that RNase similar to or identical with the pancreatic enzyme can be immunologically quantitated

Summary

Introduction

Antibodies against pure human pancreatic ribonusciloen-s of Reddi and Holland [4] orsuggest [5, 18] that the ase (RNase) were used to study ribonuclease levels in increase in the serum RNase of patients with malignant human tissues andbody fluids. We conclude that while cross-reactive proteins are found in serum or urine as well as several tissues, other immunologically distinct RNases are present, the pancreatic origin of the enzyme was postulated on the basis of a preference for poly(C) as a substrate.If verified,this observation could have important diagnostic implications; pancreatic cancer is a significant cause of death, and it is rarely detected early in its course [10,11,12] Other workers both confirm [13,14,15] and deny [16,17]the conclu-.

Methods

Results

Conclusion