Faktor-faktor yang mempengaruhi aktivitas nitrat reduktase in vivo daun kopi robusta*) (Factors affecting in vivo nitrate reductase activity of robusta coffee lea ves)
| Main Author: | Perpustakaan UGM, i-lib |
|---|---|
| Format: | Article NonPeerReviewed |
| Terbitan: |
[Yogyakarta] : Universitas Gadjah Mada
, 1987
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/21696/ http://i-lib.ugm.ac.id/jurnal/download.php?dataId=4567 |
Daftar Isi:
- ABSTRAK Factors affecting in vivo nitrate reductase activity (NRA) of rohusta coffee leaves were investigated: Enzyme activity dropped sharply at pH 8.0 � 9.0 of the incubation medium (0.1 M Na-phosphate buffer). The pH 7.5 was found to be optimal for in vivo NR assay of robusta coffee leaves. The optimum nitrate concentration was 0.1 M. The use of n-propanol and n-butanol as a buffer component were less effective than sodium dodecyl sulfate (SDS) in en-chancing enzyme activity. The optimum concentration of the organic solvent was 2% (v/v), 1% (v/v), and 0.08% (w/v), respectively. Soaking the leaf slices in buffer medium containing its component for 24 hours before assay had a negative effect. On the contrary, presoaking the leaf slices in 0.1 M Na- phosphate buffer (pH = 7.5) without its 'component for 24 hours followed by assay in buffer containing 0.08% SDS and 0.1 M NaNO, caused a significant increase in NRA. The use of leaf slices (± 1.0 c, x 0.1 cm) enhanced NRA significantly as compared to leaf discs (± 1.0 cm in diameter). Key words: nitrat reduktase, daun kopi robusta, assay