Biology Reference
In-Depth Information
Fig. 4
Protein inference of sucrose synthase in rice. The theoretical tryptic peptides are visualized for the three
known isoforms. Nodes that represent a protein are visualized in
white
, peptides that are tryptic specifi c in
red
,
peptides that are common for two isoforms in blue and peptides common to three isoforms in
green
. In order to
identify a specifi c isoform at least one tryptic specifi c peptides should be identifi ed with suffi cient confi dence.
Nodes that represent peptides that are conserved in Musa are represented as
diamonds
(color fi gure online)
5
Methods
5.1 Protein
Extraction
1. Transfer fresh plant tissue to a liquid nitrogen precooled mor-
tar and grind in liquid nitrogen (
see
Note 2
).
2. Transfer 50-100 mg of frozen tissue powder to an extraction
tube (2 ml), add 500
μ
l extraction buffer and vortex 30 s
(
see
Note 3
).
3. Add 500
l of buffered phenol and vortex 10 min at 4 °C.
4. Centrifuge for 3 min, 6,000 ×
g
at 4 °C, collect the upper
phase, i.e., the phenolic phase, and transfer to a new tube and
discard the lower phase.
μ
