A PI 4. 6 peroxidase that specifically crosslinks extensin precursors

Conference · Wed May 01 00:00:00 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-; CODEN: PPYSA
• Journal Information: Plant Physiology, Supplement; (United States), Vol. 96:1; Conference: Annual meeting of the American Society of Plant Physiology, Albuquerque, NM (United States), 28 Jul - 1 Aug 1991; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

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