Biomaterial Database

An improved procedure for the histochemical demonstration of cathepsin D by the mercury-labeled pepstatin method. 1984

S Yamato, and Y Hirabayashi, and H Sugihara

The desirable fixation conditions for the histochemical demonstration of cathepsin D using mercury-labeled pepstatin as an enzyme inhibitor were examined biochemically and histochemically. Four well known fixatives, namely, glutaraldehyde (GA), paraformaldehyde (PFA), glutaraldehyde with paraformaldehyde (GA-PFA) and periodate-lysine-paraformaldehyde (PLP), were applied to the prefixation of tissues prior to the reaction of the labeled inhibitor to the enzyme-active site. The effects of fixatives on cathepsin D were biochemically examined using subcellular fractionated lysosomes. Cathepsin D from rat liver lysosomes was rapidly inactivated by the fixatives containing glutaraldehyde, i.e., GA and GA-PFA, whereas the activity of cathepsin D was sufficiently maintained after fixing the enzyme in the PFA or PLP preparations. Effects of the PLP fixative on lysosomal cathepsin D in liver tissues using the mercury-labeled pepstatin method were also studied histochemically. The best result for the visualization of lysosomal cathepsin D in liver tissues was obtained using the PLP fixative with the prefixation time of three hours or more.

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
D008247	Lysosomes	A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured or undergoes MEMBRANE FUSION. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed).	Autolysosome,Autolysosomes,Lysosome
D008628	Mercury	A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009842	Oligopeptides	Peptides composed of between two and twelve amino acids.	Oligopeptide
D010436	Pepstatins	N-acylated oligopeptides isolated from culture filtrates of Actinomycetes, which act specifically to inhibit acid proteases such as pepsin and renin.
D002402	Cathepsin D	An intracellular proteinase found in a variety of tissue. It has specificity similar to but narrower than that of pepsin A. The enzyme is involved in catabolism of cartilage and connective tissue. EC 3.4.23.5. (Formerly EC 3.4.4.23).
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D006651	Histocytochemistry	Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.	Cytochemistry
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