Starch is the major energy source for monogastric mammals and humans. The present study was conducted to evaluate the liver metabolic responses of weaned pigs fed with different dietary starches. A total of sixteen weaned pigs were fed with two experimental diets containing either cassava starch (CS, 80 % amylopectin and 20 % amylose) or maize starch (70 % amylopectin and 30 % amylose). The pre...

We have isolated a starch mutant that was deficient in starch-branching enzyme I (BEI) from the endosperm mutant stocks of rice (Oryza sativa) induced by the treatment of fertilized egg cells with N-methyl-N-nitrosourea. The deficiency of BEI in this mutant was controlled by a single recessive gene, tentatively designated as starch-branching enzyme mutant 1 (sbe1). The mutant endosperm exhibite...

It has been well known for some time that many native prot.cins arc attacked only extremely slowly by proteolytic enzymes, or often not at all (l-6). The seeming resistance of human serum lipoproteins toward proteolysis therefore appeared to be a common phenomenon. Recently, interactions between P-lipoproteins and polyanions, in particular amylopectin sulfate, have been studied (7, 8), and this...

To examine the role of isoamylase1 (ISA1) in amylopectin biosynthesis in plants, a genomic DNA fragment from Aegilops tauschii was introduced into the ISA1-deficient rice (Oryza sativa) sugary-1 mutant line EM914, in which endosperm starch is completely replaced by phytoglycogen. A. tauschii is the D genome donor of wheat (Triticum aestivum), and the introduced fragment effectively included the...

The activities of the two types of starch debranching enzymes, isoamylase and pullulanase, were greatly reduced in endosperms of allelic sugary-1 mutants of rice (Oryza sativa), with the decrease more pronounced for isoamylase than for pullulanase. However, the decrease in isoamylase activity was not related to the magnitude of the sugary phenotype (the proportion of the phytoglycogen region of...

To understand the relationships between single nucleotide polymorphisms (SNPs) in the waxy gene and starch parameters in common rye, we performed sequence characterization, enzyme activity testing, amylopectin/amylose ratio evaluation, starch property testing, and correlation analysis. Specific primers were used to clone waxy from 20 rye cultivars. Sequence analysis showed that waxy was 2852 bp...

The major component of starch is the branched glucan amylopectin, the branching pattern of which is one of the key factors determining its ability to form semicrystalline starch granules. Here, we investigated the functions of different branching enzyme (BE) types by expressing proteins from maize (Zea mays BE2a), potato (Solanum tuberosum BE1), and Escherichia coli (glycogen BE [EcGLGB]) in Ar...

Digestion of starch in mammals occurs chiefly in the mouth and small intestine through the catalytic activity of ar-amylase and maltase (a-glucosidase). Extensive cw-amylolysis of amylose and amylopectin results in the formation of maltose, glucose, and a mixture of branched oligosaccharides (cr-amylase dextrins) (1). The latter compounds, whose structure is currently being investigated by seve...

In this study, our goal was to evaluate the role of starch debranching enzymes in the determination of the structure of amylopectin. We screened mutant populations of Arabidopsis for plants with alterations in the structure of leaf starch by using iodine staining. The leaves of two mutant lines stained reddish brown, whereas wild-type leaves stained brownish black, indicating that a more highly...

Starch is a major food supply for humanity. It is produced in seeds, rhizomes, roots and tubers in the form of semi-crystalline granules with unique properties for each plant. Though the size and morphology of the granules is specific for each plant species, their internal structures have remarkably similar architecture, consisting of growth rings, blocklets, and crystalline and amorphous lamel...