Enzymatic properties of newly found green turtle egg white ribonuclease.

Egg white ribonuclease was first found in green turtle eggs. The general properties were studied on substrate specificity, the optimum pH and temperature, and the effect of pH and temperature on the RNase activity. The enzyme studied was specific for poly (C) and degraded poly (U) at the lower rate and had the pH optimum at 7.0 and the optimum temperature at 40 degrees C. It was stable at alkaline range (pH 8.0-10.0) and up to 60 degrees C in pH 9.0 for 1 h, and unstable at acidic side for all temperatures. All of the properties studied showed similarity to RNase A. However, the optimum pH, broad range of optimum temperature and pH stability were different from RNase A. To evaluate the relationship of the structure and enzymatic properties, the 3D-structure of this enzyme was engineered by program MODELLER using two RNases (2BWL and 2BLZ) as starting models. The differences found in activity might be affected from the structure of micro environmental changing caused by amino acids deletion and substitution on the molecule.