A Simplified Procedure for the Isolation of the Sucrase · Isomaltase Complex from Rabbit Intestine Its Amino‐Acid and Sugar Composition

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Abstract
A simplified procedure for the isolation of the sucrase · isomaltase complex from rabbit small intestine was worked out, which allows the preparation of this protein in a homogeneous form in good yield.The sucrase · isomaltase complex from rabbit small intestine is a glycoprotein. It is rich in acidic amino acids; it has no free thiols in the native state but denaturation unmasks six thiols. The tyrosine/tryptophan ratio is 2. The sugar moiety(ies) (150%) is composed of d‐glucose, d‐galactose, d‐mannose, fucose, glucosamine and galactosamine (the latter two are probably acetylated). The sucrase · isomaltase complex contains no neuraminic, uronic acid, lipids, phosphate, sulfate or zinc.The partial specific volume, calculated from the amino acid and sugar composition, agrees with that experimentally determined. The hydrophobicity coefficient of this membrane protein does not differ from that of other membrane bound or water soluble proteins.