Table 2.

Antidiabetic action of peptides and protein hydrolysates identified from fish.

Source	Enzyme(s) Used	Substrate	Proteins Hydrolysates	Peptide(s) Identified	Mechanism of Action	IC50	Reference
Silver carp	Trypsin, neutrase, alcalase, papain, pepsin, and flavourzyme	Dorsal muscle	Muscle protein hydrolysates	LPIIDI	Inhibited DPP IV in vitro	105.44 μM	[76]
				APGPAGP		229.14 μM
				AGPPGPSG		Nd
				ALAPSTM		Nd
Silver carp	Papain, bromelain, alcalase 2.4 L, neutrase, and flavourzyme	Swim bladder protein	Protein hydrolysates	WGDEHIPGSPYH	Inhibited DPP IV in vitro and improved glucose uptake in INS cells	0.35 ± 0.01 mM	[77]
				IAQPQEKAPDPFRH		0.81 ± 0.01 mM
				IAGPAGPRGPAGPN		1.17 ± 0.04 mM
				VAPEEHPTL		1.93 ± 0.02 mM
				YALPHAI		2.27 ± 0.04 mM
				EPGNPGPAGPA		2.94 ± 0.01 mM
Tuna	Protease XXIII, orientase 90N	Cooking juice	Cooking juice hydrolysates	PGVGGPLGPIGPCYE	Inhibited DPP IV in vitro	116.1 μM	[78]
				CAYQWQRPVDRIR		78 μM
				PACGGFWISGRPG		96.4 μM
Blue whiting	Alcalase and flavourzyme 500	Fish meat	Meat protein hydrolysates		Inhibited DPP IV and mediated insulin and GLP-1 release from BRIN-BD11 and GLUTag cells		[79]
Salmon	Alcalase and Flavourzyme	Skin and trimmings	Protein hydrolysates		Inhibited DPP IV and mediated insulin and GLP-1 release from BRIN-BD11 and GLUTag cells		[80]

Nd—Not determined.