The biosynthetic route from uracil (2,4-dihydroxypyrimidine) to lathyrine was examined to see if during the production of 2-amino-4-carboxypyrimidine, the immediate precursor of lathyrine, ...2-amination precedes or follows 4-carboxylation. Initially, the effect of the presence of a relatively large pool of each of the possible intermediates on the incorporation of 2-
14Curacil into lathyrine by excised shoots of seedlings of
Lathyrus tingitanus was investigated. Whereas 2-amino-4-hydroxypyrimidine (isocytosine) had no significant effect, the presence of a pool of 2-hydroxy-4-carboxypyrimidine diluted the specific activity of the radioactive lathyrine synthesized to 67% of the control value without inhibiting lathyrine synthesis. In the same experiment, 2-amino-4-carboxypyrimidine, the known immediate precursor of lathyrine, decreased the specific activity to 46% of the control value without inhibiting lathyrine synthesis. In a subsequent experiment using an enzymic extract of
L. tingitanus seedlings, 2-
14Curacil was shown to be incorporated into 2-hydroxy-4-carboxypyrimidine, 2-amino-4-carboxypyrimidine and lathyrine. The data indicate that 2-hydroxy-4-carboxypyrimidine is an intermediate in lathyrine biosynthesis and that carboxylation precedes amination in the production of the lathyrine precursor 2-amino-4-carboxypyrimidine.
The CPU time required to complete a cycle of restrained least-squares refinement of a protein structure from X-ray crystallographic data using the FORTRAN codes PROTIN and PROLSQ are reported for 48 ...different processors, ranging from single-user workstations to supercomputers. Sequential, vector, VLIW, multiprocessor, and RISC hardware architectures are compared using both a small and a large protein structure. Representative compile times for each hardware type are also given, and the improvement in run-time when coding for a specific hardware architecture considered. The benchmarks involve scalar integer and vector floating point arithmetic and are representative of the calculations performed in many scientific disciplines.
A number of relatively low-cost processors are now available which employ architectural features previously found only on very expensive supercomputers. The speed of these computers makes it possible ...to reduce the time to solution of certain problems and to resolve large problems that previously were too time consuming to perform locally. A brief overview of this type of processor is given and the implications for computations in molecular biophysics are discussed in reference to the results of a benchmark that uses the refinement of a protein structure from X-ray crystallographic data.
Provider: - Institution: - Data provided by Europeana Collections- Référence bibliographique : Rol, 103530- Appartient à l’ensemble documentaire : Pho20Rol- Image de presse- All metadata published by ...Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Référence bibliographique : Rol, 94629- Appartient à l’ensemble documentaire : Pho20Rol- Image de presse- All metadata published by ...Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Référence bibliographique : Rol, 94779- Appartient à l’ensemble documentaire : Pho20Rol- Image de presse- All metadata published by ...Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Référence bibliographique : Rol, 93193- Appartient à l’ensemble documentaire : Pho20Rol- Image de presse- All metadata published by ...Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Numérisation effectuée à partir d'un document original.- Numérisation effectuée à partir d'un document de substitution.- All ...metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Numérisation effectuée à partir d'un document original.- Numérisation effectuée à partir d'un document de substitution.- All ...metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
