452
VERNON H. CHELDELIN, CHIH H. WANG, AND TSOO E. KING
tention that the depletable cellular constituents, perhaps amino acids,
were oxidized mainly by glycolysis-Krebs cycle processes and their conversion to C
14 0 2 reflects the principal respiratory mechanism, i.e., the
TCA cycle.
1 CHO
I
2 CHOH
I
3 CHOH
I
-
4 CHOH
I
5 CHOH
I
6 CH,OH
1 CH3
2 CO
I
3 COOH
4 COOH
I
5 CO
I
6CH 3
I
2 CO
I
3CH 3
4 COOH
I
5 CO
I
6CH3
1 co 2
2 CHO
I
3 CHOH
4 CHOH
I
5 CHOH
I
6 CH 2 — O+ [o]
-co2
+ [0]
-co2
+ [o]
h[0]
1 CH3
I
2 COOH
3 C02
4 C02
5 COOH
I
6CH 3
1 C02
2 COOH
I
3CH 3
4 C02
5 COOH
I
6CH 3
cycle
cycle
cycle
cycle
Extensive
pentose
cycle
Limited
pentose
cycle
22 C
I
33 C
I
32 C
44 C
I
55 C
I
66 C
2 C
I
3 C
1
5 C
1
6 C
EMP
TCA
cycle
22 CH3
1 _
33 CO 1
♦
32 COOH
44 COOH
1 _
55 CO -
4 C02
co 2
[0]
co 2
6 C02
TCA
I
66 CH3
[O]
5 C02
22 CH;
33 COOH ^
016
32 C02
44 C02
55 COOH
6 C02
5 C02
I
iCH 3
TCA t
cycle
22 C02
55 C02
33 C02
C 2 —C 3
Cleavage
4 COOH
5 CHOH
5CH 3
FIG. 8. Relative rates of C0 2 production from glucose via different pathways.
The usefulness of the radiorespirometric experiments is further
illustrated by the data given in Fig. 9 on the utilization of gluconate by
B. subtilis (145). The advantage of using C
14 specifically labeled gluconate to trace the fate of pentose phosphate is obvious inasmuch as the