Dataset Information

Two distinct secretory ribonucleases from human cerebrum: purification, characterization and relationships to other ribonucleases.

ABSTRACT: Two RNAases from human cerebrum were purified to an electrophoretically homogeneous state and their molecular masses were 22.0 kDa (tentatively called RNAase HB-1) and 19.0 kDa (RNAase HB-2). Analyses of the amino acid compositions, N-terminal amino acid sequences and catalytic properties of these enzymes provided strong evidence that they were strictly related to the secretory (sec) RNAases, such as the pancreatic enzyme, very similar immunologically to urinary sec RNAase, but clearly distinguishable from urinary non-secretory (nonsec) RNAase. There were several differences between HB-1 and HB-2, namely their immunological reactivities with specific antibodies, heat-stabilities, attached carbohydrate moieties and molecular masses. In particular, HB-2 appeared to be nonglycosylated, in view of its lack of affinity for several conjugated lectins, the absence of hexosamine and no change in electrophoretic mobility before and after peptide:N-glycosidase F digestion, whereas HB-1 and human sec RNAases purified from kidney, pancreas and urine all appeared to be glycosylated, as they moved to the same position as HB-2 when electrophoresed after glycosidase digestion. An antibody against urinary sec RNAase inhibited 75% and 20% of the total activity of the crude cerebral extract against RNA at pH 8.0 and 6.0 respectively, whereas an antibody against urinary nonsec RNAase had no such inhibitory effect. These findings suggest that yet another type(s) of cerebral RNAase, which is unable to cross-react immunologically with sec and nonsec RNAases, may exist. Two RNAases corresponding to HB-1 and HB-2 were identified in fresh cerebrospinal fluid.

SUBMITTER: Yasuda T

PROVIDER: S-EPMC1137742 | biostudies-other | 1993 Dec

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Four ribonucleases (RNAases I-IV) have been purified to homogeneity from human seminal plasma by precipitation with 40-75%-satd. (NH4)2SO4, followed by chromatographies on concanavalin A-Sepharose 4B, DEAE-cellulose phosphocellulose, agarose-5'-(4-aminophenylphospho)uridine 2'(3')-phosphate (RNAase affinity column) and Sephadex G-75 or G-100. The homogeneity of these RNAases was confirmed by polyacrylamide-gel electrophoresis. Mr values for these purified RNAases were 78 000, 16 000, 13 300 and 5000 as estimated by gel filtration. Enzyme activities of RNAases I, III and IV were inhibited by Mn2+, Zn2+ and Cu2+ and activated by Na+, K+, Ba2+, Mg2+, Fe2+ and EDTA, whereas that of RNAase II was inhibited by Ba2+, Mg2+, Fe2+, Mn2+, Zn2+ and Cu2+ and activated by Na+, K+ and EDTA. RNAases I, II and IV demonstrated a higher affinity for poly(C) and poly(U) or yeast RNA, whereas RNAase III preferentially hydrolysed poly(U) over poly(C) and yeast RNA. In the presence of 5 mM-spermine, RNAase I was dissociated to a low-Mr (5000) enzyme with an increase in total RNAase enzymic activity. Xenoantiserum to each RNAase was raised and evaluated by immunoprecipitation and immunohistochemical methods. Anti-(seminal RNAase III) antiserum showed no immunological cross-reaction with RNAases of other human origin, whereas anti-(seminal RNAase I), -(RNAase II) and -(RNAase IV) antisera exhibited indistinguishable immunological reactions with serum RNAase and other human RNAases, except that anti-(seminal RNAase I) and -(RNAase antisera IV) did not react with pancreatic RNAases. Seminal RNAases I and IV were identical immunologically as shown by anti-(RNAase I) and anti-(RNAase IV) in immunodiffusion. Immunohistochemical study revealed that, among human tissues examined, only prostate expressed seminal RNAase III. These results suggested that human seminal RNAase I may be an aggregated molecule of RNAase IV and that seminal RNAases II and IV are similar to serum RNAases, whereas seminal RNAase III is a prostate-specific enzyme.

Dataset Information

Two distinct secretory ribonucleases from human cerebrum: purification, characterization and relationships to other ribonucleases.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets