000 02186nam a2200217Ia 4500
003 MX-MdCICY
005 20250625160202.0
040 _cCICY
090 _aB-17019
245 1 0 _atRNA isopentenyltransferase from Zea mays L. Characterization of the isopentenylation reaction of tRNA, oligo (A)and other nucleic acids
490 0 _vHoppe-Seyler's Zeitschrift fur Physiologische Chemie, 359(1), p.89-101, 1978
520 3 _aThe extraction and purification of the tRNA isopentenyltransferase from maize root tips and kernels are reported. The relative amounts of this enzyme in different organs of maize have been determined. Root tips have the highest enzyme activities, followed by kernels and young leaves. Old leaves exhibit very low activity. The molecular mass of the monomeric enzyme was determined to be 57000 - 63000 dalton. pH and Mg2 optima are in full agreement with the data reported for the enzymes from yeast and Escherichia coli. Spermine enhances the isopentenylation of tRNA from kernels. The "Km" values of KMnO4-treated or untreated bulk tRNA from yeast and maize root tips and kernels were in the range of 10 to 34 micrometer while the Km values of of single species like tRNASer4 from rat liver and tRNATyrKMnO4 from E. coli were 1.1 and 6.6 micrometer, respectively. The tRNA isopentenyltransferase from maize root tips and kernels catalyzes the incorporation of 2-isopentenyl groups into (Ap)3-7A, endogenous bulk oligonucleotos from maize root tips and kernels, and into poly(A), RNA from MS-2 phages and, to a very low extent, into adenosine. The Km values of (Ap)3-7 A varied in the range of 250 to 750micrometer. Although oligonucleotides have less affinity to the enzyme, the formation of i6A within oligonucleotides may occur in vivo, due to their higher concentrations in cells.
650 1 4 _aADENOSINE
650 1 4 _aNUCLEIC ACIDO
650 1 4 _aLIGONUCLEOTIDE
700 1 2 _aHoltz, J.
700 1 2 _aKlämbt, D.
856 4 0 _uhttps://drive.google.com/file/d/1dZA9A5ddYAmq9yD9zt0rPQZwtRgkoFym/view?usp=drivesdk
_zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx
942 _2Loc
_cREF1
008 250602s9999 xx |||||s2 |||| ||und|d
999 _c51182
_d51182