METABOLIC PATTERN OF PHOSPHOLIPIDS DURING GERMINATION OF MUNG BEAN, PHASEOLUS RADIATUS VAR TYPICUS .I. INCORPORATION OF 32P-ORTHOPHOSPHATE INTO PHOSPHOLIPIDS

Swollen shelled seeds or etiolated seedlings after three days' germination of mung bean, Phaseolus radiatus var. typicus were incubated with 32P-orthophosphate solution at 30°C in the dark. The 32P incorporation into phospholipids in the cotledons of the former, or in the hypocotyls and radicles of the latter was observed by time course study in terms of their water-soluble deacylation products. The greater part of the incorporated radioactivity was observed in glycerophosphorylcholine (GPC) from the cotyledons, and in glycerophosphorylethanolamine (GPE) from the hypocotyls and radicles. Specific radioactivity was given as follows in decreasing order: Glycerophosphorylserine (GPS), GPC>GPE> glycerophosphorylinositol (GPI) in the cotyledons, and GPS>GPE>GPC in the hypocotyls and radicles. The specific radioactivity of GPI fraction was remarkable in the hypocotyls and radicles. The different patterns of phospholipid metabolism observed between the cotyledons and the hypocotyls and radicles were discussed in connection with biosynthetic pathways of phosphatidylcholine. © 1969 BY THE JOURNAL OF BIOCHEMISTRY.