Biomaterial Database

Demonstration of an altered S-adenosylmethionine synthetase in human malignant tumors xenografted into athymic nude mice. 1980

M C Liau, and C F Chang, and B C Giovanella

S-Adenosylmethionine synthetase isoenzymes (EC 2.5.1.6) were studied in human malignant tumors xenografted into athymic nude mice and were studied in normal human and rat tissues. The tumors included 7 melanomas; 4 colon carcinomas; 3 each of mammary, cervical, and ovary carcinomas; 2 each of lung carcinomas and sarcomas; and 1 each of lymphoma and stomach and nasopharyngeal carcinomas. The presence of an altered intermediate Michaelis constant (Km) isoenzyme, previously shown to be a unique characteristic of rat neoplastic tissues, in these tumors was invariably detectable, though the presence of the low-Km isoenzyme characteristic of the enzyme of normal tissues was also evident in many of these tumors. Only tumors demonstrating high rates of growth were devoid of the low-Km isoenzyme. The low-Km isoenzyme was the only enzyme detectable in many normal human and rat tissues. Thus this isoenzyme was probably the common enzyme of all tissues. Some additional organ-specific isoenzymes were found, e.g., in the liver and lactating mammary gland. The low-Km isoenzyme in malignant tumors was altered to assume a considerably higher Km value, and this alteration appeared to be a common aberration of malignant tumors.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008716	Methionine Adenosyltransferase	An enzyme that catalyzes the synthesis of S-adenosylmethionine from methionine and ATP. EC 2.5.1.6.	S-Adenosylmethionine Synthetase,ATP-Methionine S-Adenosyltransferase,ATP Methionine S Adenosyltransferase,Adenosyltransferase, Methionine,S Adenosylmethionine Synthetase,S-Adenosyltransferase, ATP-Methionine,Synthetase, S-Adenosylmethionine
D008819	Mice, Nude	Mutant mice homozygous for the recessive gene "nude" which fail to develop a thymus. They are useful in tumor studies and studies on immune responses.	Athymic Mice,Mice, Athymic,Nude Mice,Mouse, Athymic,Mouse, Nude,Athymic Mouse,Nude Mouse
D009368	Neoplasm Transplantation	Experimental transplantation of neoplasms in laboratory animals for research purposes.	Transplantation, Neoplasm,Neoplasm Transplantations,Transplantations, Neoplasm
D009369	Neoplasms	New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.	Benign Neoplasm,Cancer,Malignant Neoplasm,Tumor,Tumors,Benign Neoplasms,Malignancy,Malignant Neoplasms,Neoplasia,Neoplasm,Neoplasms, Benign,Cancers,Malignancies,Neoplasias,Neoplasm, Benign,Neoplasm, Malignant,Neoplasms, Malignant
D009374	Neoplasms, Experimental	Experimentally induced new abnormal growth of TISSUES in animals to provide models for studying human neoplasms.	Experimental Neoplasms,Experimental Neoplasm,Neoplasm, Experimental
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
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
D014018	Tissue Distribution	Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.	Distribution, Tissue,Distributions, Tissue,Tissue Distributions