Maize plastids polymerase

RNA polymerase activity in chloroplasts was first described by Kirk (1964), who studied broad beans. In addition, a soluble RNA polymerase in maize leaf homogenates has been described by Mans and Novell (1964). In the present investigations an RNA polymerase has been found in purified maize chloroplasts. Data on the localization of this enzyme are given in Table 2. The enzyme catalyzes the incorporation of nucleotide triphosphates into a trichloroacetic acid-pre-cipitable material. All four nucleotide triphosphates are required for activity, the enzyme is inhibited by RNase, DNase, and dactinomycin, and its activity is not stimulated by the inclusion of polyribonucleotides. With purified plastids the activity of the enzyme is stimulated by deoxyribonucleotides. Table 3 shows data from three different preparations of plastids isolated from illuminated or unilluminated leaves there is clearly greater activity in illuminated leaves. 

The Effect op Illumination op Etiolated Maize Leaves ON Plastid RNA Polymerase Activity... 

The activity of RNA polymerase in proplastids from chloramphenicol-treated leaves maintained in darkness is lower than in proplastids from controls. Furthermore, illumination of chloramphenicol-treated etiolated leaves results in some increase in plastid RNA polymerase, but the response is much smaller than that exhibited by plastids from illuminated controls (Table 4). These observations suggest that RNA polymerase is forming and decaying in etiolated maize proplastids in darkness but that the rate of formation is increased by light. On the other hand, the activity of the soluble RNA ploymerase found outside... 

Effect of Administration of Chloramphenicol to Etiolated Maize Leaves on RNA Polymerase Activity of Isolated Plastids... 

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