Agriculture Reference
In-Depth Information
C
YTOPLASMIC
F
RUCTOSE
-1,6-B
ISPHOSPHATASE
Recombinant pea cytoplasmic fructose-1,6-bisphosphatase is thermostable
and active in the pH range 6.6-9.0. The activation energy is 17.4 kcal/mol,
Arrhenius frequency factor is 2.6 x 10(12)/s. K(M) was 10.47 microM, and
V(max) is 109 micromol/min. The recombinant enzyme is competitively
inhibited by fructose-2,6-bisphosphate and non-competitively inhibited by
AMP (Jang et al., 2003).
R
AFFINOSE
S
YNTHASE
Steady-state kinetic analysis suggested that pea seed raffinose synthase is
a transglycosidase adopting a ping-pong reaction mechanism. The activity of
pea seed enzyme is markedly suppressed by 1-deoxygalactonojirimycin which
inhibits alpha-galactosidases (Peterbauer et al., 2002).
B
ETA
-K
ETOACYL
-A
CYL
C
ARRIER
P
ROTEIN
S
YNTHASE
III
A 42-kDa dimeric beta-ketoacyl-acyl carrier protein (ACP) synthase III
from pea leaves demonstrating amino acid sequence similarity to counterparts
from other plants is uncompetitively inhibited by thiolactomycin but is
competitively inhibited by a thiolactomycin derivative with a longer (C8
saturated) hydrophobic side-chain (compound 332) (Jones et al., 2003).
C
ASPASES
Caspase-like proteases are important to the developmental cell death of
secondary shoots of pea seedlings that appear following elimination of the
epicotyl. Caspase-like activity is upregulated in aging secondary shoots, but
not in dominant growing shoots, unlike papain-like cysteine protease activity
which prevails in the dominant shoot. Revitalization of the aging shoot by
removal of the dominant shoot causes the caspase-like activity to undergo a
decline. Administration of caspase or cysteine protease inhibitors into the
residual epicotyl tissue inhibits the death of the secondary shoots, generating
