Reaction catalyzed by pepsin A (3.4.23.1)

		+			=		(3R,4R)-4-(2,2-dimethyl-1,3-dioxolan-4-yl)-1,3,4-trihydroxybutan-2-one
	(R)-(+)-2,2-dimethyl-1,3-dioxolane-4-carbaldehyde	+		1,3-dihydroxypropan-2-one	=		(3R,4R)-4-(2,2-dimethyl-1,3-dioxolan-4-yl)-1,3,4-trihydroxybutan-2-one