Biomaterial Database

Purine biosynthesis and its regulation in Neurospora crassa. 1980

L Pendyala, and A M Wellman

Purine biosynthesis and its regulation was studied in Neurospora crassa by the incorporation of label from [14C]formate into total cellular purines. In general, the purine biosynthesis resulted in slightly more cellular guanine than adenine nucleotides. The acid-soluble pool however, contained more adenine compounds than guanine. Exogenous adenine was found to be an effective regulatory of the proximal steps of the de novo biosynthesis, while both adenine and guanine were equally effective in regulating the branch point activities. 6-Methyl purine inhibited the proximal steps of the purine synthesis more effectively than the branch point leading to adenine biosynthesis. A 6-methyl purine resistant mutant, Mepr-10, with defective adenine phosphoribosyl pyrophosphate transferase showed no inhibition of purine synthesis by 6-methyl purine, while 6-methyl purine resistant strains Mepr-3 and Mepr-1 showed partial inhibition. It has been suggested that Mepr-3 and Mepr-1 may be mutants of glutamine amidotransferase with altered affinities for 6-methyl purine. The rate of purine biosynthesis increased during the first 8 h of incubation of conidia in minimal medium, after which it declined even though the growth continued.

UI	MeSH Term	Description	Entries
D008727	Methotrexate	An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of TETRAHYDROFOLATE DEHYDROGENASE and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA.	Amethopterin,Methotrexate Hydrate,Methotrexate Sodium,Methotrexate, (D)-Isomer,Methotrexate, (DL)-Isomer,Methotrexate, Dicesium Salt,Methotrexate, Disodium Salt,Methotrexate, Sodium Salt,Mexate,Dicesium Salt Methotrexate,Hydrate, Methotrexate,Sodium, Methotrexate
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009491	Neurospora	A genus of ascomycetous fungi, family Sordariaceae, order SORDARIALES, comprising bread molds. They are capable of converting tryptophan to nicotinic acid and are used extensively in genetic and enzyme research. (Dorland, 27th ed)	Neurosporas
D009492	Neurospora crassa	A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.	Chrysonilia crassa
D011687	Purines	A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
D004351	Drug Resistance	Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.	Resistance, Drug
D005561	Formates	Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.	Formic Acids,Acids, Formic
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