Alpha-(1,4) exo-glucosidase involved in breakdown of dietary starch oligosaccharides in small intestine. Cleaves the non-reducing alpha-(1,4)-linked glucose residue in linear dextrins with retention of anomeric center stereochemistry (PubMed:12547908, PubMed:18356321, PubMed:27480812, PubMed:18036614, PubMed:22058037). Mainly hydrolyzes short length oligomaltoses having two to seven glucose residues (PubMed:12547908, PubMed:18356321, PubMed:27480812, PubMed:18036614, PubMed:22058037). Can cleave alpha-(1,2), alpha-(1,3) and alpha-(1,6) glycosidic linkages with lower efficiency, whereas beta glycosidic linkages are usually not hydrolyzed (PubMed:27480812). Hydrolysis of terminal, non-reducing (1->4)-linked alpha-D-glucose residues with release of alpha-D-glucose. D-maltoheptaose + H2O = alpha-D-glucose + D-maltohexaose D-maltohexaose + H2O = alpha-D-glucose + D-maltopentaose D-maltopentaose + H2O = alpha-D-glucose + D-maltotetraose D-maltotetraose + H2O = alpha-D-glucose + D-maltotriose D-maltotriose + H2O = alpha-D-glucose + D-maltose D-maltose + H2O = alpha-D-glucose + D-glucose H2O + nigerose = alpha-D-glucose + D-glucose H2O + kojibiose = alpha-D-glucose + D-glucose H2O + isomaltose = alpha-D-glucose + D-glucose 6-O-alpha-D-glucopyranosyl-D-fructose + H2O = alpha-D-glucose + D-fructose Down-regulated at high oligomaltose concentration as it occurs during the mealtime (PubMed:18356321). Down-regulated by anti-diabetic drug acarbose (PubMed:18036614, PubMed:22058037). Optimum pH is 7. Has substantial activity at acidic pH. Carbohydrate degradation. Monomer. Brush border. Broadly expressed. Highly expressed in small intestine. Expressed in granulocytes. The N-terminal maltase domain (ntMGAM) mainly hydrolyzes short length oligomaltoses having two to four glucose residues. The C-terminal glucoamylase domain (ctMGAM) acts on longer maltoside substrates having four to seven glucose residues. N- and O-glycosylated. Does not undergo intracellular or extracellular proteolytic cleavage. Sulfated. The displayed isoform 2 sequence is inferred based on alignments, homology, conservation, expression and longest protein. RNA-seq transcriptomic analysis supports all introns in a single sample. No single full-size mRNA sequence supports this isoform yet, however it is clearly identified by mass spectrometry analysis. Belongs to the glycosyl hydrolase 31 family.