Characterization of 38 kDa and 42 kDa chitinase isozymes from the liver of Japanese common squid Todarodes pacificus

Abstract

Characterization was investigated on the 38 kDa and 42 kDa chitinase (EC3.2.1.14) isozymes from the liver of Japanese common squid Todarodes pacificus. Optimum pH toward colloidal chitin was observed at pH 3.0 for the 38 kDa chitinase, and pH 3.0 and 9.0 for the 42 kDa chitinase. Km and kcat of the 38 kDa and 42 kDa chitinases toward a longer substrate, glycol chitin, were 0.071 mg/mL and 1.22/s, and 0.074 mg/mL and 0.196/s, respectively. Alternatively, strong substrate inhibition of both chitinases were observed toward a short substrate, N‐acetylchitopentaose (GlcNAc5). Both chitinases decomposed not only chitin but also chitosan (D. A. 95%). The cleavage pattern and reaction rate were investigated using N‐acetylchitooligosaccharides (GlcNAcn, n = 2–6). Both chitinases hydrolyzed GlcNAcn (n = 4,5, and 6). The release of GlcNAc was not observed. The speed of the reaction was observed to be in the following order: GlcNAc4 > GlcNAc5 > GlcNAc6 for the 38 kDa chitinase, and GlcNAc6 > GlcNAc5 > GlcNAc4 for the 42 kDa chitinase. Both the chitinases released p‐nitrophenol from p‐nitrophenyl GlcNAcn (n = 2, 3, and 4). N‐terminal amino acid sequences of the 38 kDa and 42 kDa chitinases were YLLSXYFTNWSQYRPGAGKYFPQNI and EYRKVXYYTNWSQYREVPAKFFPEN, respectively.

Purification and Characterization of a Highly Thermostable Chitinase from the Stomach of the Red ScorpionfishScorpaena scrofawith Bioinsecticidal Activity toward Cowpea WeevilCallosobruchus maculatus(Coleoptera: Bruchidae)

“…[4][5][6][7][8] They are abundant in nature, occurring in plants, animals, viruses, bacteria, fungi, and insects, and they have various functions, including defense, nutrient digestion, morphogenesis, and pathogenesis. 9) Chitinases found in the stomachs of fish [10][11][12][13] and livers of squids 14,15) have, for instance, been found to degrade chitinous substances ingested as food, and chitinases present in insects and shellfish have been found to degrade chitinous substances in exoskeletons during ecdysis. [16][17][18] In plants, on the other hand, chitinases act as proteins for self-defense against fungal pathogens that contain chitinous substances.…”

THE EVIDENCE OF NON N-GLYCAN LINKED MANNOSE IN EXOCHITINASE (42 kDa) FROM Trichoderma harzianum BIO10671 GLYCOSYLATION

“…The protein size revealed by SDS-PAGE for T. harzianum BIO10671 was 42 kDA which was larger than the purified chitinase collected by Deane et al [6] from T. harzianum T198, but similar to the range of endochitinases reported previously by Ulhoa and Peberdy [21], Haran et al [8] and Matsumiya et al [14]. The molecular weight of purified chitinase may differ between species and also within species [19] and it is not known whether they are differently processed gene products from the same gene or from separate genes.…”

Kinetic Analysis of a Chitinase from Red Sea Bream,Pagrus major

“…Alignment of the amino acid sequences of red sea bream chitinase is done with other family 18 and 19 chitinases such as Homo sapiens (AAG60019.1), 31) Bombyx mori (BAB20017.1), 33) Manduca Sexta (AAC04924.1), 27) Todarodes pacificus, 30) Penaeus japonicus, 32) Nicotiana tabacum (AAB23374), Arabidopsis thaliana (BAA82818), and Dioscorea oppositifolia (BAC56863). Identical residues are enclosed in boxes.…”