A PI 4. 6 peroxidase that specifically crosslinks extensin precursors

Conference · Wed May 01 04:00:00 EDT 1991 · Plant Physiology, Supplement; (United States)

OSTI ID:5403613

Upham, B L; Alizadeh, H; Ryan, K J; Lamport, D T.A. ^[1]

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1. Michigan State Univ. Plant Research Lab., East Lansing (United States)

The primary cell wall is a microcomposite of cellulose, pectin, hemicellulose and protein. The warp-weft model of the primary cell wall hypothesize that extensin monomers are intermolecularly crosslinked orthogonal to the cellulose microfibril thus mechanically coupling the major load-bearing polymer: cellulose. Media of tomato cell cultures contains heat labile, peroxide dependent crosslinking activity, as determined by the rate of decrease in monomer concentration analyzed via Superose-6. Isoelectric focusing of tomato cell culture media indicated crosslinking was predominantly in the acidic peroxidase fraction (pI4.6). This peroxidase was partially purified by ultracentrifugation, DEAE-Trisacryl and HPLC-DEAE chromatography techniques resulting in a 90 fold purification and 45% yield. A second acidic peroxidase eluted from the HPLC-DEAE column had 25% of the crosslinking activity of the pI 4.6 peroxidase. Purified basic peroxidase had only 0.7% of the activity of the pI 4.6 peroxidase. The specific activity of the pI 4.6 peroxidase was 5,473 mg extensin crosslinked/min/mg peroxidase. The pI 4.6 peroxidase crosslinked the following extensins: tomato I and II, carrot, Ginkgo II and did not crosslink Ginkgo I, Douglas Fir, Maize, Asparagus I and II, and sugarbeet extensins as well as bovine serum albumin. Comparison of motifs common to extensins that are crosslinked by the pI 4.6 peroxidase may help identify the crosslink domain(s) of extension.

• OSTI ID: 5403613
• Report Number(s): CONF-9107184--
• Conference Information: Journal Name: Plant Physiology, Supplement; (United States) Journal Volume: 96:1
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALBUMINS
BEETS
BIOCHEMICAL REACTION KINETICS
CARBOHYDRATES
CARROTS
CELL CONSTITUENTS
CELL CULTURES
CELL WALL
CELLULOSE
CEREALS
CHEMICAL REACTIONS
CONIFERS
CROSS-LINKING
ENZYMES
FIRS
FOOD
FRUITS
GRAMINEAE
KINETICS
LILIOPSIDA
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MAIZE
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PEROXIDASES
PHYSIOLOGY
PINOPHYTA
PLANT CELLS
PLANTS
POLYMERIZATION
POLYSACCHARIDES
PRECURSOR
PROTEINS
REACTION KINETICS
SACCHARIDES
SUGAR BEETS
TOMATOES
TREES
VEGETABLES