Acid ribonuclease

El-Sewedy, S.M., M.H. Mostata, E.A. El-Bassiouni, A. Abdel-Rafee, and A.H. El-Sebae. 1982. Effect of fenvalerate on kynurenine metabolizing enzymes and acid ribonuclease of mouse liver. Jour. Environ. Sci. Health B17 571-579. 

Walters and Loring (88) have purified a 3 -nucleotidase about 50-fold from mung bean sprouts (Phaseolus aureus Roxb.). The enzyme hydrolyzes 3 -AMP, 3 -GMP, 3 -CMP in decreasing order and also hydrolyzes the 3 -phosphate group of coenzyme A. (89), but it has no significant activity for 2 - or 5 -ribonucleotides. For 3 -GMP, 3 -AMP, 3 -UMP, and 3 -CMP, Km values are 0.67, 1.1, 7.7, and 15 mM, respectively. The enzyme preparation also contained acid stable ribonuclease activity (89). Both 3 -nucleotidase and acid ribonuclease were inactivated reversibly at pH 5.0 and by dialysis and this inactivation could be prevented by Zn2+. The two activities were similarly inactivated by heat at pH 5 and 7.5. Such data indicate that the two are metalloproteins— probably zinc metalloproteins. These similarities and other kinetic data provide evidence that the 3 -nucleotidase and ribonuclease activities reside in the same protein. 

Amino acid Ribonuclease A8 Ribonuclease B8 Glucoamylase I7 Glucoamylase II7 External invertase63 Internal invertase63... 

This final acid phosphatase preparation had a specific activity of 468 and represented an approximately 1900-fold purification of the acid phosphatase in the starting crude spleen nuclease II. It contained no acid deoxyribonuclease, acid ribonuclease, exonuclease, and phosphodiesterase activities that could be detected in a 0.1-ml sample after 2 hours of incubation with the appropriate substrate. The relative rates of hydrolysis of various substrates were as follows p-nitrophenyl phosphate, 100 5 -AMP, 63 j8-glycerophosphate, 60 ATP, 0. With p-nitrophenyl phosphate as substrate, the pH optimum was broad and lay between pH 3.0 and pH 4.8. The Michaelis constant at 37°C was 7.25 X 10" mM. Phosphate and chloride ions acted as competitive inhibitors. 

Affinity chromatography of acid ribonuclease 268 from He La cell lysosomes demonstration that the enzyme is a glycoprotein Purification of human liver acid a-D- 148... 

Hydrol. product of yeast ribonucleic acid. Ribonuclease inbibitor. 

Lysozyme (parenteral) Renal tubule Cathepsin, acid ribonuclease Acid phosphatase Maack (1967)... 

Post-CCL injury Liver Cathepsin, aiysulfatase, acid ribonuclease Acid phosphatase glucuronidase Dianzani (1963) Shoitman (1962) Slater et al. (1963)... 

Zinc/iminodiacetic acid Ribonuclease A. transferrin, carbonic anhydrase, lactoferrin, venom phospholipase... 

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