Diverse Distribution of Four Distinct Types of Modori (Gel Degradation)-Inducing Preoteinases Among Fish Species

Abstract

Modori-inducing proteinase (MIP) could be classified into four types as follows on the basis of the extractability from muscle, the optimum temperature for the activity of myosin heavy chain degradation, and the sensitivity to n-butanol (1) Sarcoplasmic-50°C-MIP (Sp-50-MIP) which is easily extractable, acts optimally at 50°C, and is not sensitive to n-butanol, (2) sarcoplasmic-60°C-MIP (Sp-60-MIP) which is also easily extractable, acts optimally at 60°C, and is sensitive to n-butanol, (3) myofibrillar-50°C-MIP (Mf-50-MIP) which is tightly associated with myofibrils, acts optimally at 50°C, and is not sensitive to n-butanol, and (4) myofibrillar-60°C-MIP (Mf-60-MIP) which is also tightly associated with myofibrils, acts optimally at 60°C, and is sensitive to n-butanol. Twelve fish species examined were classified into the following five groups according to the distribution pattern of the above 4 types of MIP. (1) The species having only Sp-60-MIP, such as walleye pollack, mud dab, rainbow trout, brown croaker and red sea bream, (2) the species having both Sp-50-MIP and Sp-60-MIP, such as threadfin bream, (3) the species having both Mf-50-MIP and Mf-60-MIP, such as crucian carp, Pacific mackerel and file fish, (4) the species having both Sp-60-MIP and Mf-60-MIP, such as nibe croaker and tilpia, and (5) the species having Sp-60-MIP, Mf-50-MIP, and Mf-60-MIP, such as shortfin lizard fish. © 1990, The Japanese Society of Fisheries Science. All rights reserved.