A partial cystatin cDNA from rainbow trout was
generated by reverse transcription polymerase chain reaction
with two degenerate primers. The partial cystatin PCR
product was 168 bp and used to screen trout liver λgt 11
cDNA library. Four positive clones were isolated and
designated as cstl, cst2, cst3 and cst4....
Kinetic properties of the two proteases, causing textural degradation of Pacific
whiting (Merluccius productus) during heating, were compared and characterized with the
synthetic substrate, Z-Phe-Arg-NMec. Pacific whiting P-I and P-II showed the highest
specificity on Z-Phe-Arg-NMec, specific substrate for cathepsin L. The K [subscript m] of
preactivated P-I and P-II...
Proteinase P-II purified from parasitized Pacific whiting muscle was previously
identified to be one form of cathepsin L. It appeared to be present in three isozymatic
forms on non-denaturing PAGE gel stained for activity. Its autolytic degradation was
observed on SDS-PAGE gel under its optimum condition, 55°C and pH 5.5,...
Cathepsin B was the most active cysteine proteinase in the Pacific whiting
(Merluccius productus) fish fillet, and cathepsin L in surimi when the activities of the
most active cysteine proteinases (cathepsin L, B, and H) were compared. Cathepsin L
showed maximum activity at 55°C in both fish fillet and surimi,...
Proteolytic degradation of fish flesh occurring at elevated temperatures is the
primary limitation for the commercial utilization of arrowtooth flounder (ATF).
Characterization of the autolytic activity of ATF muscle incubated at various pHs
and temperatures indicated the involvement of heat-activated proteinases active at
acidic and alkaline pHs. Further characterization of...
Bacterial histamine formation in mackerel and albacore was studied by inducing histamine in the muscles under controlled storage conditions. The optimum temperature for histamine formation was 25°C. The highest level of histamine detected was 283 mg/100 g in the 2-day stored mackerel; and 67.1 mg/100 g in the 6-day stored...
High proteolytic activity Pacific whiting muscle causes hydrolysis of myofibrillar protein and lowers surimi gel quality. Although food grade proteinase inhibitors can be used to prevent autolytic activity in surimi, their usage is limited due to their adverse effects on the organoleptic quality of surimi. Cystatins however can be used...
Proteolysis of myofibrillar proteins in Pacific whiting surimi occurs when the 50-
70°C temperature range is reached during standard cooking procedures (e.g. 90°C for 15
min). This proteolytic activity results in the softening of surimi gels. Bovine plasma
protein (BPP) is the most effective of the food-grade inhibitors used to...