There is considerable evidence that a critical reaction in purine synthesis is the closure of the purine ring by the addition of a “formate” group to 4-amino-5-imidazolecarboxamide ribonucleotide (1). Apparently the “formate” is added as an active intermediate, since formate as such has little effect in stimulating purine synthesis. Indeed, there is a demonstrable difference in the utilization ...

In the title mol-ecule, C(3)H(5)N(5)O(2), the tetra-zole ring and carboxyl group form a dihedral angle of 82.25 (14)°. In the crystal, adjacent mol-ecules are linked through O-H⋯N, N-H⋯O and N-H⋯N hydrogen bonds into layers parallel to the bc plane.

N-Protected derivatives of 1-amino-cyclo-hexa-neacetic acid (β(3,3)-Ac6c), namely Valeroyl-β(3,3)-Ac6c-OH [2-(1-pentanamidocyclohexyl)acetic acid, C13H23NO3], (I), Fmoc-β(3,3)-Ac6c-OH [2-(1-{[(9H-fluoren-9-yloxy)carbonyl]amino}cyclohexyl)acetic acid, C23H25NO4], (II), and Pyr-β(3,3)-Ac6c-OH {2-[1-(pyrazine-2-amido)cyclohexyl]acetic acid, C13H17N3O3}, (III), were synthesized and their conformati...

Human platelet lysates contained potent mitogenic activities for MCF-7 human breast-cancer cells in serum-freedefined media. Because these activities were not replaced by known platelet mitogens. such as platelet-derived growth factor or transforming growth factor , we sought to identify the breast cancer cell mitogens by purification and N amino-acid sequencing. Acetic acid extracts of outdate...

Human platelet lysates contained potent mitogenic activities for MCF-7 human breast-cancer cells in serum-freedefined media. Because these activities were not replaced by known platelet mitogens. such as platelet-derived growth factor or transforming growth factor , we sought to identify the breast cancer cell mitogens by purification and N amino-acid sequencing. Acetic acid extracts of outdate...

The first intermediates in the metabolism of thiamine by a microorganism isolated from soil are Z-methyl-4-amino-5hydroxymethylpyrimidine and 5-(2-hydroxyethyl)-4-methylthiazole. The pyrimidine is further metabolized, first to 2-methyl-4hydroxy-5-hydroxymethylpyrimidine followed by 2-methyl4-hydroxy-5-pyrimidine-carboxylic acid. The thiazole metabolites 4-methylthiazole-5-acetic acid and 2-oxyd...

pea seedlings incorporate a variety of C14-amino acids into their protein. The incorporation is promoted by adenosine triphosphate, by a mixture of amino acids, by magnesium and potassium ions (5), and by the nucleosides derived from ribonucleic acid (6). Amino acid incorporation is inhibited by adenosine diphosphate, by amino acid analogues, by rubidium ions, by certain purine analogues, and b...

Several fused imidazolopyrimidines were synthesized starting from 6-amino-1-methyl-2-thiouracil (1) followed by nitrosation, reduction and condensation with different aromatic aldehydes to give Schiff's base. The dehydrocyclization of Schiff's bases using iodine/DMF gave Compounds 5a-g. The methylation of 5a-g using a simple alkylating agent as dimethyl sulfate ((CH₃)₂SO₄) gave either monoalkyl...