Biomaterial Database

Vitamin B6 metabolism in McA-RH7777 cells. 1988

N T Meisler, and J W Thanassi

Department of Biochemistry, University of Vermont College of Medicine, Burlington 05405.

The metabolism of vitamin B6 in McA-RH7777 cells has been characterized with respect to pyridoxal 5'-phosphate (PLP) levels, and the activities of pyridoxine (PN) kinase (EC 2.1.7.35) and pyridoxine 5'-phosphate (PNP) oxidase (EC 1.4.3.5). PLP levels (12.4 +/- 4.4 ng/mg protein) were at the lower end of the range found for Morris hepatomas, carcinogen-induced rat hepatomas, and liver from rats fed a PN-deficient diet. PN kinase activity was about one-third of that found in normal rat liver. PNP oxidase appeared to be absent in high-speed supernatants of homogenates prepared from McA-RH7777 cells. The absence of PNP oxidase was supported by enzymatic and immunological data. These findings resemble those found previously for Morris hepatoma 7777. In contrast to rat liver, such preparations caused little or no release of volatile counts upon incubation with either [3H-C4']PN or [3H-C4']PNP. High-speed supernatants of homogenates prepared from both McA-RH7777 cells and Morris hepatoma 7777 were very much less capable than similar preparations from rat liver in converting [G-3H]PN to PLP and pyridoxamine 5'-phosphate. Despite the apparent absence of PNP oxidase, intact confluent or log-phase McA-RH7777 cells were capable of converting [G-3H]PN to PLP and pyridoxamine 5'-phosphate. These findings are discussed in terms of tumor nutrition and vitamin B6 metabolism in a rat hepatoma cell line.

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
D008114	Liver Neoplasms, Experimental	Experimentally induced tumors of the LIVER.	Hepatoma, Experimental,Hepatoma, Morris,Hepatoma, Novikoff,Experimental Hepatoma,Experimental Hepatomas,Experimental Liver Neoplasms,Hepatomas, Experimental,Neoplasms, Experimental Liver,Experimental Liver Neoplasm,Liver Neoplasm, Experimental,Morris Hepatoma,Novikoff Hepatoma
D011731	Pyridoxal Kinase	An enzyme that catalyzes reversibly the phosphorylation of pyridoxal in the presence of ATP with the formation of pyridoxal 5-phosphate and ADP. Pyridoxine, pyridoxamine and various derivatives can also act as acceptors. EC 2.7.1.35.	Pyridoxamine Kinase,Pyridoxine Kinase,Pyridoxal Phosphokinase,Kinase, Pyridoxal,Kinase, Pyridoxamine,Kinase, Pyridoxine,Phosphokinase, Pyridoxal
D011732	Pyridoxal Phosphate	This is the active form of VITAMIN B 6 serving as a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate (PYRIDOXAMINE).	Pyridoxal 5-Phosphate,Pyridoxal-P,Phosphate, Pyridoxal,Pyridoxal 5 Phosphate,Pyridoxal P
D011734	Pyridoxaminephosphate Oxidase	An enzyme catalyzing the deamination of pyridoxaminephosphate to pyridoxal phosphate. It is a flavoprotein that also oxidizes pyridoxine-5-phosphate and pyridoxine. EC 1.4.3.5.	Pyridoxinephosphate Oxidase,Pyridoxine-5-Phosphate Oxidase,Oxidase, Pyridoxaminephosphate,Oxidase, Pyridoxine-5-Phosphate,Oxidase, Pyridoxinephosphate,Pyridoxine 5 Phosphate Oxidase
D011736	Pyridoxine	The 4-methanol form of VITAMIN B 6 which is converted to PYRIDOXAL PHOSPHATE which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. Although pyridoxine and Vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading (EE Snell; Ann NY Acad Sci, vol 585 pg 1, 1990).	Pyridoxin,Pyridoxine Hydrochloride,Pyridoxol,Pyridoxol Hydrochloride,Rodex
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
D014407	Tumor Cells, Cultured	Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.	Cultured Tumor Cells,Neoplastic Cells, Cultured,Cultured Neoplastic Cells,Cell, Cultured Neoplastic,Cell, Cultured Tumor,Cells, Cultured Neoplastic,Cells, Cultured Tumor,Cultured Neoplastic Cell,Cultured Tumor Cell,Neoplastic Cell, Cultured,Tumor Cell, Cultured
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus