Biomaterial Database

Characterization of ribonucleases and ribonuclease inhibitor in subcellular fractions from rat adrenals. 1966

N S Girija, and A Sreenivasan

1. The presence of two RNA-degrading enzymes, one with optimum activity at pH5.6 (acid ribonuclease) and the other with optimum activity at pH7.8 (alkaline ribonuclease), in rat adrenals has been demonstrated. The acid ribonuclease was localized in the mitochondrial fraction whereas the alkaline ribonuclease was present in mitochondria as well as in the supernatant fraction. Freezing and thawing of mitochondria and treatment with Triton X-100 gave a three- to four-fold increase in acid-ribonuclease activity, whereas the mitochondrial alkaline-ribonuclease activity was practically unaffected. 2. The amount of free ribonuclease in the adrenal supernatant was small. Treatment of the supernatant fraction with N-ethylmaleimide resulted in release of large amounts of ribonuclease activity, indicating the presence of a ribonuclease inhibitor having reactive thiol groups. 3. Considerable amounts of free ribonuclease inhibitor in excess over the bound alkaline ribonuclease are present in the rat-adrenal supernatant fraction. The inhibitor is heat-labile and non-diffusible. A 400-500-fold purification of the ribonuclease inhibitor was achieved by ammonium sulphate fractionation, treatment with calcium phosphate gel and DEAE-cellulose chromatography. It is concluded that the adrenal inhibitor is protein in nature, similar to the inhibitor present in rat liver.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D002845	Chromatography	Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.	Chromatographies
D004798	Enzymes	Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.	Biocatalyst,Enzyme,Biocatalysts
D005033	Ethylmaleimide	A sulfhydryl reagent that is widely used in experimental biochemical studies.	N-Ethylmaleimide,N Ethylmaleimide
D000311	Adrenal Glands	A pair of glands located at the cranial pole of each of the two KIDNEYS. Each adrenal gland is composed of two distinct endocrine tissues with separate embryonic origins, the ADRENAL CORTEX producing STEROIDS and the ADRENAL MEDULLA producing NEUROTRANSMITTERS.	Adrenal Gland,Gland, Adrenal,Glands, Adrenal
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012260	Ribonucleases	Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.	Nucleases, RNA,RNase,Acid Ribonuclease,Alkaline Ribonuclease,Ribonuclease,RNA Nucleases,Ribonuclease, Acid,Ribonuclease, Alkaline
D013347	Subcellular Fractions	Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)	Fraction, Subcellular,Fractions, Subcellular,Subcellular Fraction