Differentiation of the properties of the branching isozymes from maize (Zea mays)

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Plant Physiology; (United States)

OSTI ID:5696124

Guan, H P; Preiss, J ^[1]

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1. Michigan State Univ., East Lansing, MI (United States)

The multiple forms of branching enzyme (BE) from developing maize (Zea mays) endosperm were purified by modification of previous procedures such that amylase activity could be eliminated completely from the BE preparation. Three distinct assays for BE activity (phosphorylase a stimulation assay, BE linkage assay, and iodine stain assay) were used to characterize and differentiate that properties of the BE isoforms. This study present s the first evidence that the BE isoforms differ in their action on amylopectin. BEI has the highest activity in branching amylose, but its rate of branching amylopectin was less than 5% of that of branching amylose. Conversely, BEII isoforms had lower rates in branching amylose (about 9--12% of that of BEI) and had higher rates of branching amylopectin (about 6-fold) than BEI. The implication of these findings to the mechanism of amylopectin synthesis in vivo are discussed. 21 refs., 1 figs., 5 tabs.

• OSTI ID: 5696124
• Journal Information: Plant Physiology; (United States), Vol. 102:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ENZYMES
CHEMICAL PROPERTIES
PROTEIN STRUCTURE
MAIZE
ENDOSPERM
PECTINS
BIOSYNTHESIS
AMYLASE
BLOOD SUBSTITUTES
BODY
CARBOHYDRATES
CEREALS
DRUGS
GLYCOSYL HYDROLASES
GRAMINEAE
HEMATOLOGIC AGENTS
HYDROLASES
LILIOPSIDA
MAGNOLIOPHYTA
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
PLANT TISSUES
PLANTS
POLYSACCHARIDES
PROTEINS
SACCHARIDES
SYNTHESIS
TISSUES
550200* - Biochemistry