Biology Reference
In-Depth Information
Table 4.4 Conversion of exogenous 5-aminolevulinic acid (ALA) to Chl(ide)
a
and
b
(nmol per 100 mg plastid protein) by isolated etiochloroplasts
Incubation time [min]
0
Exp.
Irradiation
Tetrapyrrole
15
30
60
A
2.5 ms
MV Chlide
a
3.1
0.4
-
-
3.1
0.3
MV Chl
a
21.8
6.1
-
-
14.7
2.1
MV Chlide
b
0.3
0.0
-
-
0.4
0.2
MV Chl
b
0.7
0.2
-
-
0.8
0.5
B
24 h
MV Chlide
a
45.1
0.6
-
-
180.3
13.7
MV Chl
a
11849.5
1137.7
-
-
12325.0
205.1
MV Chlide
b
12.5
3.9
-
-
24.1
0.8
MV Chl
b
4380.4
177.2
-
-
4577.4
316.2
C
4 h
MV Chlide
a
14.3
5.3
-
43.0
8.3
64.7
12.7
MV Chl
a
97.3
19.6
-
181.7
11.7
108.6
4.0
MV Chlide
b
1.9
0.3
-
4.3
2.1
6.9
1.3
MV Chl
b
18.5
4.4
-
33.2
2.1
22.7
0.1
D
3.0
MV Chl
a
138.0
15.7 272.9
8.8 244.7
14.4 200.8
4.5
MV Chlide
b
1.8
0.1 2.8
0.1 5.9
1.0 7.0
0.2
MV Chl
b
35.0
1.9 59.4
0.9 70.9
2.0 62.1
2.3
Etiochloroplasts were prepared from etiolated cucumber cotyledons pretreated with “white light” as follows:
A:
2.5 ms actinic flash followed by 60 min of
darkness;
B:
120 nmol/m2/s for 24 h; C and
D:
120 nmol/m
2
/s for 4 h. Each incubation contained 0.05 ml of 10 mMALA (about 10.4-13.8 nmol, depending on
the protein content of the plastids). The endogenous ALA content amounted to an insignificant amount of about 0.003 nmol per 100 mg plastid protein
All values
standard deviation are means of two replicates
4 h
MV Chlide
a
12.1
0.7
25.3
2.4
52.3
1.2
55.0
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