Glutamine synthetase of hevea brasiliensis latex : characterisation and physiological regulation (Record no. 60009)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 02443nam a2200277Ia 4500 |
| 100 ## - MAIN ENTRY--AUTHOR NAME | |
| Personal name | Clement Anne |
| 245 #0 - TITLE STATEMENT | |
| Title | Glutamine synthetase of hevea brasiliensis latex : characterisation and physiological regulation |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Name of publisher | Journal of Rubber Research |
| Year of publication | 2001 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Number of Pages | 56-68 |
| 520 ## - SUMMARY, ETC. | |
| Summary, etc | Regular exploitation of rubber tree causes intense metabolic activity in latex cells located in the phloem, associated with the regeneration of the latex cellular components removed by tapping. In this context, glutamine synthetase (GS) plays a prominent role by ensuring ammonium fixation necessary for the regeneration of latex nitrogeneous components. In latex, GS activity was detected in the cytosol only. The enzyme was purified and its main physico-chemical characteristics were determined. Its molecular mass was 450 kDa for the native form and 45kDa +_ 5kDa for the sub-unit. The pH optimum was found to be 8.0 and variaitons in the physiological pH range (6.4 to 7.2) strongly affected GS activity. Km for ammonium, glutamate and ATP were estimated at 8mM +_ 2 mM +_ 5 mM and 0.6 mM +_ 0.05 mM, respectively. Comparison with the cytosol physiological parameters showed the importance of ATP concentration for GS activity regulation. Functioning of the purified enzyme in a paraphysiological (ultrafiltrated, protein free) medium, as compared with an optimised control medium, demonstrated that physiological ATP concentrations were significantly limiting for GS potential activity. Treatment with ethephon increases latex production both by increasing latex flow duration and by stimulating the regeneration of metabolism. In this paper we demonstrated that ethephon treatment induced a concomitant increase in pH, ATP concentration and GS activity. These results suggest that biochemical mechanisms involving pH and ATP participate in the regulation of GS activity in response to ethylene, in addition to the previously observed stimulation of gene expression. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Biochemical analysis |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Characterisation |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Ethephon |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Glutamine synthetase |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | GT1 |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Hevea brasiliensis |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Latex stimulation |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Physiological regulation |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical Term | Purification |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Hirel B |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Jacob Jean-Louis |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Prevot Jean-Claude |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Pujade-Renaud V |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Koha item type | Journals |
| Withdrawn status | Lost status | Damaged status | Not for loan | Home library | Current library | Shelving location | Date acquired | Serial Enumeration / chronology | Koha item type |
|---|---|---|---|---|---|---|---|---|---|
| Journals | RRII Library | RRII Library | Physiology | 17/12/2021 | Volume 4, Issue 1 | Journals |