Reaction catalyzed by pepsin A (3.4.23.1)

		+			=		(3R,4S)-3,4-dihydroxy-6-methylheptan-2-one
	3-methylbutanal	+		1-hydroxypropan-2-one	=		(3R,4S)-3,4-dihydroxy-6-methylheptan-2-one