Digestive protease in blacklip abalone (Haliotis rubra Leach) from whole gut extracts was found to have dual pH optima at pH 3 and 10 and an optimum temperature of 45°C. Over the biologically relevant range of pH (5-8), protease activity dropped to a minimum at pH 5 (53% of the maximal rate at pH 3) rising gradually and continuously up to (and beyond) pH 8. Over the biologically relevant range of temperatures (9-24°C), protease activity increased continuously with activity at 24°C being 75% higher than activity at 9°C. Protease digestion was relatively uniform in gut extracts from sections containing gut contents. Digestion thus appears to be significantly extracellular (in the lumen of the gut). Analysis of gut sections washed free of food matter suggests the anatomical origin of protease from activity of gut regions in the order: digestive gland » salivary gland ≈ stomach > crop > intestine > upper oesophagus. Whole gut protease levels did not alter in response to a high protein artificial diet.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Biochemistry and cell biology
Research Field:	Enzymes
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Fisheries - aquaculture
Objective Field:	Fisheries - aquaculture not elsewhere classified
UTAS Author:	Edwards, SJ (Dr Steve Edwards)
UTAS Author:	Condon, CF (Mr Christopher Condon)
ID Code:	22531
Year Published:	2001
Web of Science® Times Cited:	18
Deposited By:	Health Sciences A
Deposited On:	2001-08-01
Last Modified:	2011-09-20
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