rebaudioside A + UDP-alpha-D-glucose => rebaudioside D + UDP + H(+)
rebaudioside a + udp-alpha-d-glucose => rebaudioside d + udp + h(+)
rebaudioside A + UDP-alpha-D-glucose => rebaudioside D + UDP + H(+)
rebaudioside a + udp-alpha-d-glucose => rebaudioside d + udp + h(+)