| Gene/protein | Names / identifiers | Enzyme class | Predicted domains / architecture | Approx. length / mass | Likely localization | Inducing conditions / expression context | Recent biochemical examples / notes | Key supporting citations |
|---|---|---|---|---|---|---|---|---|
| **CHIB (target gene)** | **Endochitinase B; ChitB; seed chitinase B; UniProt P29023; gene model GRMZM2G005633** | **EC 3.2.1.14; glycoside hydrolase family 19 (GH19); class IV plant endochitinase** | **Signal peptide present; chitin-binding domain (CBD; cd00035) present; catalytic domain (cd00325) present; class IV GH19 architecture** | **~281–282 aa; predicted mature protein ~29 kDa** | **Likely secreted / apoplastic or extracellular, consistent with signal peptide and seed/pathogenesis-related chitinase annotation** | **Transcript abundance and total chitinase activity increase after mechanical wounding and fall armyworm herbivory; high organ expression reported in seed; Table 1 image supports SP/CBD/domain assignment** | **Direct CHIB-specific kinetic constants were not provided in the retrieved excerpts; function is inferred as an endochitinase that hydrolyzes β-1,4 linkages in chitin, consistent with GH19 catalytic mechanism** | (pqac-00000001, pqac-00000002, pqac-00000003, pqac-00000010) |
| **ZmChi19A (comparison only; different maize GH19 gene, not CHIB)** | **Zea mays basic endochitinase; root-associated GH19 chitinase** | **GH19; class I endochitinase** | **N-terminal hevein-like CBD; α-helical catalytic domain; flexible C-terminal domain; catalytic residues E147 and E169** | **Not summarized in retrieved excerpt** | **Root-secreted / rhizosphere-associated** | **Studied as a root-associated defense enzyme; antifungal activity against *Aspergillus niger*** | **Apparent Km ~30 µM for 4-MU-GlcNAc3; optimum around pH 7–9 and 50–60°C (more specifically pH 8 and 50°C in one excerpt); CBD and flexible C-terminal domain are required for efficient colloidal chitin cleavage and fungal growth inhibition** | (pqac-00000005, pqac-00000006, pqac-00000007, pqac-00000008) |


*Table: This table summarizes the core functional annotation for the maize CHIB/ChitB protein targeted in the report, using evidence that specifically matches UniProt P29023 and the maize gene model GRMZM2G005633. It also includes a clearly separated comparison row for a different maize GH19 chitinase, ZmChi19A, to illustrate recent biochemical parameters available for related GH19 enzymes.*