Specific activities of acid, alkaline and neutral proteases in liver, muscle, brain, and gill of fish exposed to 50 ppm ambient carbamide for 15, 30 and 60 days and in control were estimated. It was observed that carbamide even at low concentration of 50 ppm inhibited proteolysis and favoured protein synthesis

Neeraja, P.

Perviz, D.A.

Rajyasree, M.

Aquatic Commons

Journal of the Indian FiDheries ABsociation 113 
25, 1995 (Proc.Nat.Symp. Aquacrops), 113-117 
EFJ1~ECT OF FERTU . .IZER CARBANIIDE ON PROTEOLYTIC 
ENZYMES OF FISH LABEO ROHI'I'A 
M. RAJYASREE, P. NEERAJA"' AND DABEER A. PERVIZ 
Osmania University, Hyderubad 
Specific activities of acid, alkaline and neutral protease.s in liver, 
ntuscle, brain, and gill of fish exposed to 50 ppm ambient carbamide for 
15, 30 and 60 days and in conh·ol were estimated. It was observed that 
carban1ide even at low concentration of 50 ppm inhibited proteolysis and 
favm.lTed protein synthesis. 
Proteolytic enzymes of animal tissue 
· have been a subject of interest and 
research since many years. Proteasos are 
mainly of acidic, alkaline and neutral 
based on their specificity in action with 
reference to optimum hydrogen ion 
concentration. The degradation involved 
in the continuous turnover of cellular 
proteins which are meuiated by proteasos 
is not clear (Young, 1970; Schimke, 
1973). Information on catheptic enzymes 
from tissues of mammals (Barrett, 1977) 
is voluminous but scant on those of 
aquatic species. Lysosomal proteases 
show main role in cellular protein 
degradation (Ballard, 1977; Marzella et 
al., 1981). A cell when exposed to new 
environment alters the protein 
composition. Proteolysis indicates tissue 
degeneration resulting in cellular and 
biochemical functions. The protease 
activity of tissues is known to increase 
in various physiological and pathological 
conditions. Hence, an attempt has been 
made to study the effect of carbamide on 
different proteases of Labeo rohita. 
~' S. V. University, Tirupati. 
Labeo rohita (20±2 g) brought from 
local fisheries department and 
maintained in the laboratory at 28±2°C 
and photoperiod of 12hr darkness and 
12 hr light, were used in the pret::>cnt 
investigation. They were fed with 1:1 
ratio of ground nut oil cake and rice bran, 
the quantity being 2% of the body weight. 
Carbamide at a concentration of 50 ppm 
was selected as an experimental dose 
after due standardisation. Proteases 
were assayed by the method of Davis 
and Smith (1955). Statistical significance 
of the difference between .control (c) and 
experimental (E) values was calculated 
using Students 't' test (Pillai and Sinha, 
1968). 
The specifh~ activities of acid, 
alkaline and neutral proteases was found 
to decrease in diflerent tissues of fish 
exposed to 50ppm of carbamide for 15,30 
and 60 days (Fig. 1,2 and 3). Acidic 
protease during the initial 15 days 
showed an increased activity but on 
·exposure to carbamide for 30 and 60 days 
de-escalation was observeli in all tissues 
(Fig. 1). Carbamide exposure decreased 
114 NOTES 
the specific activity of alkaline protease 
in all tissues during the entire period of 
exposure (Fig. 2). The responses of 
neutral protease to carbamide, exhibited 
slight elevation on 15 days but 
. . ,' ~. 
subsequent decrement in liver, gill, 
muscle and brain tissues in 30 and 60 
days was observed (Fig. 3). 
0 
L 
..., 
c 
0 
u 
L 
10 
0 
-10 
-20 
-30 
r--
t-
1-
....__ 
1-
.___ 
1-
1-
~ 0 ,..-,----.--.-..----,---,--
0 
OJ 
(J\ ....__ 
c 
0-10 -
.c 
u 
-
~ 
-20 1-
1-
-30 t-
1- @.Liver 
15 30 60 
Proteases in L. rohita were estimated 
for assessing the possible involvement 
of tissue proteaSE$ in the regulation of 
protein metabolism under carbamide 
stress. Inhibition of proteolytic activities 
is a regulatory step towards inhibiting 
the tissue proteolysis (Rajyasree, 1984). 
The observed trends in the activity levels 
-
1-
1-
@.Gill 
1- L---
r-
1-
1-
I-
1- CB. Muscle ..._____ 
15 30 GO 
Exposure period <oaysl 
Fig. 1 :Activity of acidic protease on different tissues of L.rohita exposed to carbamide 
NOTES 115 
Exposure period (Days) 
15 30 50 15 30 50 
-10 
-20-
-30-
-40 
0 
L.. § 
u 
~ 
0 
~ 
0 -10 
Q) 
1... 
u 
Q) 
a 
-zo-
~ 
-30-
-
-40-
-
-50-
-
-
-
-
-
-
-
-
©.Muscle 
-
-
-
-
-
@.Brain - G). Gill 
Fig. 2 :Activity of alkaline protease on different tissues of L.rohita exposed to carbamide 
of proteases was indicative of low degree 
of regulation on the tissue proteolysis,· 
probably oriented towards maintaining 
the integrity of the structures. Decrease 
in activity levels of proteases suggests 
decreased proteolysis thereby decrease 
in the extent of structural disintegrations 
during carbamide stress. Under normal 
condition the native and denatured 
proteins of the tissue exists in 
equilibrium (Surugi and Ogata, 1977). 
Thus initial increment in protease may 
be due to increased succeptability of 
protein content (denatured) and 
enhanced activity could be the result of 
higher protein turnover. As an acid 
proteases is a lysosomal enzyme 
decreased acidic protease might be due 
116 NOTES 
-101-
-20-
-30 f-
0 @ Liver @ Gill 
'-
..... 
c 0 0 (.) 
'- f-Q) 
> 0 
-10 r- 1-Q) 
0\ 
-c 
0 L..--
.c 
-20 _-u r 
~ 
-30 
- -
(61 Muscle ©.Brain 
1'3 30 60 15 30 60 
Expo sure period (Days) 
Fig. 3: Activity of neutral protease on different tissues of L.rohita exposed to carbamide 
to inactivation of enzyme or .less effect 
of carbamide on lysosomal structure. 
Though there was initial increment in 
proteolytic enzyme, the decrement in 
prolonged exposure suggested the 
possibility of elevation of protein 
turnover to regulate both the enzyme 
synthesis and degradation (Martin, et al., 
1981). Neutral protease (or) physiological 
protease are i1 volved in breakdown of 
proteins ready for the formation of Free 
Amonio Acids. The elevation in neutral 
proteases of liver and gill appeared to 
be advantageous to the animal since 
these organs remain intact without being 
disrupted by protease and thus 
maintenance of structural organisation. 
to a great extent i.e., the protein 
NOTES 117 
breakdown was not favoured at neutral Rodwell, V. W. 1981. Harpers 
pH. Initial increment shows metabolic Review of Biochen1,istry. (18th ed.) 
significance in bringing out possible Lange Medical Publications, 
physiological compensation to carbamicie Maruaen Asia Pvt. Ltd. 
stress. Alkaline protease acts during 
process of protein degradation (Mayer et 
al., 1974). In order to inhibit protein 
degradation the alkaline protease might 
have decreased and less contribution of 
alkaline proteases to increased protein 
metabolism is suggestive. 
Thus the proteases 1n general 
showed a decreasing trend on carbamide 
stress suggesting greater maintenance of 
structural integrity and lesser 
degradation of the tissue protein. 
ACKNOWLEDGEMENTS 
The first author is thankful to The 
C.S.I.R., New Delhi for financial support 
through a Research Associateship. 
REFERENCES 
Ballard F. J. 1977. Intracellular protein 
degradation Ess. Biocem. 13 : 1-37. 
Barrett, A. J. 1977. Introduction to the 
history and· classification of tissue 
proteinases. Proteinases 1n 
mammalian cells & tissues. Barrett 
A. J. (Ed..) Elseiver, Ed, 1-55. 
Davis, N. C. and Smith, E. L. 1955 
Assay of .Proteolytic enzymes In: 
Methods in Biochemical Analysis 
Glick, ·D. (Ed.) Inter Science 
Publishers, New York 247 pp. 
Martin, D. W., Mayer, P. A. and 
Marzella, L. AU berg. J. and 
Glaumann, H. 1981 Autophagy, 
microphagy & crinophages as the . 
means of intracellular degrada-tion. 
Virchows Arch. B. Cell. Pathol. 36: 
219-234. 
Mayer, M., Amin, R. and Shafrir, E. 
197 4. Rat myafibrillar proteases 
Enzyme properties and adaptive 
changes in conditions of muscle 
protein degradation. Arch. Biochem. 
Biophys. 161 : 20-25 
PIHai, S. K. and Sinha, H. C. 1968. 
Statistical method for biological 
workers. Ramprasad & Sons, Agra. 
Rajyasree, M. 1989. Metabolic 
alterations in Fish, Cyprinus Carpio 
on Exposure to Ambient Urea. M. 
Phil dissertation, S.V. University 
Tirupati, India. 
Shimke, R. T. (Ed). '1973. Advances in 
Enzymology. Meister Wiley, New 
York : 135 pp. 
Surugi, T .. and Ogata, K. 1977. 
Preferential degradation of newly 
synthesized ribosomal proteins in rat 
liver treated with low dose of 
actinomycin. D. Biochem. Biophys. 
Res. Comm. 47 : 1127-1162. 
Young, V. R. 1970. Mammalian Protein 
Metabolism. (Ed. H. N. Munro), Vol. 
4. Academic press, New York : 585 
pp. 


Effect of fertilizer carbamide on proteolytic enzymes of fish Labeo rohita

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Effect of fertilizer carbamide on proteolytic enzymes of fish Labeo rohita

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