472 Produce Degradation: Reaction Pathways and their Prevention
FIGURE 15.5
Pectin degradation by pectin methyl esterase, polygalacturonase, and pectin lyase. (From Agrios, 1997. With permission.)
O
O
O
...
O
O
...
O
O
O
HH
O
OH HO
O
...
O
...
O
O
...
...
...
COOH
COOH
COOH
O
COOH
+
CH
OH 3
Methanol
H OH
COCH
3
O
C
H
OCH
3
O
++
O
O
O
O
O
...
O
O
O
O
O
COOH
COOH
O
COOH
COCH
3
O
O
COOO
CH
3
O
O
COCH
3
O
COCH
3
O
COCH
3
O
(PME)
(PG)
(PL)
Pectin methyl esterase
Pectin lyase (PL)−H
2 O
Polygalac-turonase(PG)
+ H
O 2
+ H
O 2
(PME)