COMPARATIVE BIOINFORMATICS-BASED ANALYSIS OF DIGESTIVE ENZYMES IN THE JAPANESE SEA CUCUMBER (Apostichopus japonicus)

10th International ICONTECH CONGRESS, Ankara, Turkey, 24 - 26 July 2026, pp.147-155, (Full Text)

The Japanese sea cucumber (Apostichopus japonicus) is an ecologically important detritivorous species

that contributes significantly to benthic ecosystem functioning and organic matter recycling. This study

aimed to comprehensively investigate the domain architecture and evolutionary conservation of major

digestive enzymes involved in carbohydrate, protein, and lipid digestion through comparative

bioinformatics analyses. Eight representative digestive enzymes were examined: α-amylase, maltase-

glucoamylase, lysosomal α-glucosidase, mannosyl-oligosaccharide glucosidase, sucrase-isomaltase,

pancreatic triacylglycerol lipase, trypsin, and cathepsin L. Protein sequences were analyzed using

BLASTP, the Conserved Domain Database (CDD), and Pfam to compare functional domain architectures

across representatives of the echinoderm classes Holothuroidea, Echinoidea, Asteroidea, and Crinoidea.

The analyses revealed that the catalytic domains of GH31 family glycosidases and the Tryp_SPc domain

of trypsin are highly conserved throughout the phylum, reflecting strong evolutionary constraints

associated with their essential digestive functions. In contrast, variation in the distribution and copy

number of auxiliary domains, including Trefoil, PD, CUB, and LDLa, suggests lineage-specific structural

adaptations related to ecological specialization and physiological diversification. Overall, these findings

provide new insights into the molecular basis of sediment-based feeding strategies in sea cucumbers and

advance our understanding of the evolution of digestive enzymes and protein domain architecture within

Echinodermata.