Molecular control of nitrate reductase in Chlorella vulgaris /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | Thermal effects on enzymic rates were determined from continuous thermal gradients generated by an electronic temperature controller and monitored with a microprocessor-controlled spectrophotometer. Absorbance, time, and temperature data were collected and used directly to determine activation energies and temperature coefficients. This technique was used to determine the thermal dependence of two of the reactions catalyzed by nitrate reductase from Chlorella vulgaris. Activation energies were determined to be 42.1 kJ/mol for NADH:nitrate oxidoreductase (EC 1.6.6.1) and 21.5 kJ/mol for NADH:cytochrome c oxidoreductase (EC 1.6.99.3). The importance of stringent temperature control during nitrate reductase assays and the need to report the temperature of assay are reported. The nitrate reductase (NR) of Chlorella vulgaris can exist in vivo in a reversibly inactivated cyanide-bound form. It was suggested that other forms might exist, but none have been reported. It is shown here that the cyanide inactivated form is the only major inactive form found in Chlorella vulgaris under the conditions here employed. Early events in the process of NR induction were examined. Both total NR protein and levels of translatable mRNA for NR were monitored. NR protein and NR mRNA were found to be present in low levels in cells prior to induction. NR protein exists under these conditions primarily as lower molecular mass degradation products. NR mRNA is found at low levels but translates in vitro to yield full sized precursor. Consistent with earlier research, there is an over production of NR protein during early induction. Concomitantly, there is an over production of its mRNA. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Biochemistry." |
| Physical Description: | xi, 148 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 137-139). |