Reaction catalyzed by 1-phosphatidylinositol-5-phosphate 4-kinase (2.7.1.149)

	ATP	+			=		ADP	+
	ATP	+		1-phosphatidyl-1D-myo-inositol 3-phosphate	=		ADP	+		1-phosphatidyl-1D-myo-inositol 3,4-bisphosphate