Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2007
Publication Date: 6/1/2007
Citation: Lackeyram, D., Nichols, B.L., Fan, M.Z. 2007. The small intestinal maltase-glucoamylase activity increases during the postnatal growth in pigs [abstract]. Journal of Federation of American Societies for Experimental Biology. 21(6):A1060. Interpretive Summary:
Technical Abstract: The small intestinal maltase-glucoamylase (MGAM) contributes to the starch digestion pathway in the small intestine. This study investigated ontogenic changes of MGAM in the hydrolysis of amylose along the longitudinal axis of the small intestine. Jejunal tissue was collected from pigs belonging to each of seven age groups (d 1, 4, 6, 12, 20, 28, and 70, n = 6) for MGAM enzyme kinetic experiments. The jejunum was divided into halves with the end closest to the stomach designated proximal (Px) jejunum and the other half designated the distal (Dt). Kinetic experiments of MGAM activity were conducted with six levels of purified amylose (0-100 micro M) at 37 degrees C and pH 6.0. On average postnatal growth increased (P<0.05) the MGAM maximal specific activity (Vmax: d 1, 2.11 +/- 0.02 to d 70, 5.51 +/- 0.09, nmol/mg protein.min, n= 36) by 161% and increased (P<0.05) the enzyme affinity (Km: d 1, 31.99 +/- 1.51 to d 70, 18.51 +/- 1.19, µM, n=36) by 42%. Additionally, the proximal jejunum had consistently higher (P<0.05) Vmax (d 70: Px, 8.00 +/- 0.04 vs. Dt, 3.01 +/- 0.03 nmol/mg protein.min, n= 36) and lower enzyme affinities (d 70: Km: Px, 24.96 +/- 0.0.51 vs. Dt, 12.06 +/- 0.88 micro M, n=36). Thus, postnatal growth was associated with a dramatic increase in the maximal specific activity of MGAM for the hydrolysis of amylose in pigs. The maximal activity of MGAM was consistently higher but the enzyme affinity lower in the proximal than in the distal jejunum throughout the growth in the pig.