Studies on carbohydrate-metabolizing enzymes. 12. A survey of the carbohydrases of alfalfa.

The presence of a number of carbohydrases in alfalfa (lucerne, Medicago sativa) seeds and seedlings has been reported, including o-D-glucosidase, a-D-galactosidase, fl-D-fucosidase, P-N-acetyl-Dglucosaminidase (Levvy & McAllan, 1962), f-Dglucosidase, ,B-D-galactosidase and M-D-mannosidase (Hill, 1934; Levvy & McAllan, 1962). A comparative study of almond and alfalfa 'emulsins' has also been made (Hill, 1934). Studies of the mature plant appear to be limited to the pectinesterase activity (Lineweaver & Ballou, 1945; MacDonnell, Jansen & Lineweaver, 1945; MacDonnell, Jang & Jansen, 1950). In most previous studies, glycosidase activities were tested against synthetic and natural glycosides with non-carbohydrate aglycones. A survey of the oligosaccharideand polysaccharide-degrading enzymes has now been undertaken with a view to the assessment of their possible use in the structural analysis of alfalfa components. The carbohydrases probably bear some relation to the carbohydrate components of the plant. Apart from the reserve galactomannan of the seed (Hirst, Jones & Walder, 1947; Courtois, Anagnostopoulos & Petek, 1958), and the pectic substances and hemicellulose of the mature plant (Aspinall & Fanshawe, 1961; Myhre & Smith, 1962), little is known of the high-molecular-weight components of alfalfa. Small quantities of starch are present in the leaves of the plant (Hirst, Mackenzie & Wylam, 1959), though this is likely to show a marked diurnal variation, as in the related clover (Bailey, 1958). Fructosans, which form the main carbohydrate reserves of grasses, appear to be absent (Hirst et al. 1959). The raffinose-stachyose series of oligosaccharides, together with sucrose, appear to comprise the oligosaccharide component in alfalfa (Aspinall & Fanshawe, 1961; Meunie, 1936).