Characterization of seven basic endochitinases isolated from cell cultures of Citrus sinensis (L.)

• Published in: Planta Vol. 200; no. 3; pp. 289 - 295
• Main Authors: Mayer, R.T, McCollum, T.G, Niedz, R.P, Hearn, C.J, McDonald, R.E, Berdis, E, Doostdar, H. (US Dept. of Horticulture, Orlando, Florida (USA). Agricultural Research Service)
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 1996; Springer
• Subjects: Acetates; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; ANTIBODIES; ANTICORPS; ANTICUERPOS; Biological and medical sciences; Biotechnology; CAL; CALLO; CALLUS; CELL CULTURE; CELL WALLS; CELLS; CELLULE; CELULAS; Chitin; CHITINASE; Chitinases - chemistry; Chitinases - isolation & purification; Chitinases - metabolism; Chitosanase; Citrus - enzymology; CITRUS SINENSIS; CULTIVO DE CELULAS; CULTURE DE CELLULE; Electrophoresis, Polyacrylamide Gel; ENZIMAS; ENZYME; ENZYME INHIBITORS; ENZYMES; Enzymes and enzyme inhibitors; ENZYMIC ACTIVITY; Fundamental and applied biological sciences. Psychology; Glycoside Hydrolases - chemistry; Glycoside Hydrolases - isolation & purification; Glycoside Hydrolases - metabolism; HIDROLISIS; HISTAMINA; HISTAMINE; HISTIDINA; HISTIDINE; Hydrolases; HYDROLYSE; HYDROLYSIS; IMIDAZOLE; IMIDAZOLES; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; LISOZIMA; LYSOZYME; Metabolism; Molecular Sequence Data; Molecular Weight; Muramidase - chemistry; Muramidase - isolation & purification; Muramidase - metabolism; OLIGOSACARIDOS; OLIGOSACCHARIDE; OLIGOSACCHARIDES; PARED CELULAR; PAROI CELLULAIRE; Pathogenese-related-Protein; Plant physiology and development; PLANT TISSUES; Plants; PROTEINAS; PROTEINE; PROTEINS; QUITINASA; Sodium; Substrate Specificity; TEJIDOS VEGETALES; Tetrasaccharides; TISSU VEGETAL; Ultrafiltration; Chitinase; Cell culture; Citrus sinensis; Enzyme; Citrus fruit; Rutaceae; Pathogenesis related protein; Characterization; Enzymatic activity; Dicotyledones; Glycosidases; Substrate specificity; Angiospermae; Chitosanase; N terminal-Sequence; Hydrolases; Spermatophyta; O-Glycosidases; Lysozyme
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/bf00200295

Seven endochitinases (EC 3.2.1.14) (relative molecular masses 23000—28000 and isoelectric points 10.3—10.4) were purified from nonembryogenic Citrus sinensis L. Osbeck cv. Valencia callus tissue. The basic chitinase/lysozyme from this tissue (BCLVC) exhibited lysozyme, chitinase and chitosanase activities and was determined to be a class III chitinase. While BCLVC acted as a lysozyme at pH 4.5 and low ionic strength (0.03) it acted as a chitinase/chitosanase at high ionic strengths (0.2) with a pH optimum of ca. 5. The lysozyme activity of BCLVC was inhibited by histamine, imidazole, histidine and the N-acetyl-D-glucosamine oligosaccharide (GlcNAc)3. The basic chitinase from cv. Valencia callus, BCVC-2, had an N-terminal amino acid sequence similar to tomato and tobacco AP24 proteins. The sequences of the other five chitinases were N-terminal blocked. Whereas BCLVC was capable of hydrolyzing 13.8—100% acetylated chitosans and (GlcNAc)4—6 oligosaccharides, BCVC-2 hydrolyzed only 100% acetylated chitosan, and the remaining enzymes expressed varying degrees of hydrolytic capabilities. Experiments with (GlcNAc)2—6 suggest that BCLVC hydrolysis occurs in largely tetrasaccharide units whereas hydrolysis by the other chitinases occurs in disaccharide units. Cross-reactivities of the purified proteins with antibodies for a potato leaf chitinase (AbPLC), BCLVC, BCVC-3, and tomato AP24 indicate that these are separate and distinct proteins.