Studies on the size and shape of rabbit intestinal glucoamylase-maltase complex

Abstract

Rabbit intestinal glucoamylase-maltase was examined in detail with respect to its molecular weight, sedimentation, diffusion and viscosity. It is a large asymmetrical molecule, with a molecular weight of 750000-760000. Its appearance under the electron microscope supports the idea that it is a long string (62.0nm) consisting of eight beads of diameter 6.0nm each and a surface-to-surface interbead distance of approx. 2.0nm. The shape of the enzyme derived from its hydrodynamic behaviour by using the string-of-spherical-beads model originally proposed by Kuhn [(1932 ) ,.

Neutral maltase/glucoamylase from rabbit renal cortex

“…In rabbit kidney the maltase and glucoamylase exist as a complex similar to that of the intestine, 6 pH 46 -since the two activities do not separate during conventional purification procedures. The Mr value of 590000 of the native enzyme is close to the value of 760000 of the intestinal enzyme complex (Sankaran et al, 1983). The Stokes radius of the kidney enzyme as estimated by gel filtration is 7.4 nm, whereas that of the intestinal enzyme is 12 nm (Sankaran et al, 1983).…”

“…The Mr value of 590000 of the native enzyme is close to the value of 760000 of the intestinal enzyme complex (Sankaran et al, 1983). The Stokes radius of the kidney enzyme as estimated by gel filtration is 7.4 nm, whereas that of the intestinal enzyme is 12 nm (Sankaran et al, 1983).…”

“…Though the physicochemical properties of the intestinal enzyme have been investigated in detail, the number and nature of the subunits and their interactions are not clear (Sankaran et al, 1983). The kidney enzyme seems to possess a simpler quaternary structure, being made up of eight identical subunits linked by disulphide bridges.…”

“…In the present paper we report a method for the purification of detergentsolubilized maltase from rabbit kidney cortex and some of its properties. The results are compared with those obtained with the enzyme from rabbit small intestine (Sankaran et al, 1983).…”

Small intestine mucosal α-glucosidase: A missing feature of in vitro starch digestibility

“…In the early 328 1960's, the distinction among various mucosal α-glucosidases is based on their thermal 329 stability. NtMGAM has higher thermo stability than CtMGAM, and the CtMGAM is more 330 tolerant to heat than SI(Kelly & Alpers, 1973;Kolinska & Kraml, 1972;Sankaran, …”