Table IV.

DMSP-amine does not act as a trapping pool for label from [³⁵S]SMM

S. alterniflora leaf sections (0.2 g fresh weight) were incubated for 4 h with 18.5 kBq (0.15 nmol) of [³⁵S]SMM, with or without a 5-μmol trapping pool of unlabeled DMSP-amine. The size of the DMSP-amine pool in the tissue was estimated in a parallel experiment in which leaf sections were incubated with 5 μmol (18.5 kBq) of [³⁵S]DMSP-amine for 4 h. The values shown are per 0.2 g fresh weight and have been corrected for recovery. The experiment was repeated using an 8-h incubation time, with similar results.

DMSP-amine Trap		[35S]SMM Uptake	Label Distribution
Supplied	In tissue		SMM	DMSP-amine	DMSP
nmol		kBq	kBq	Bq	kBq
0	0	5.22	1.96	111	2.52
5000	568	2.44	1.48	126	0.78