Demonstration of carboxyl and thiol protease activities in adultSchistosoma mansoni, Dirofilaria immitis, Angiostrongylus cantonensisandAscaris suum

Abstract

Evidence has been presented showing two kinds of acidic protease activities in adult Schistosoma mansoni, Dirofilaria immitis, Angiostrongylus cantonensis and Ascaris suum. A haemoglobinolytic activity without adding any SH-containing compounds was maximal at pH 3.5, 2.5, 30 and 3.5 in S. mansoni, D. immitis, Angiostrongylus cantonensis and Ascaris suum respectively. The inhibitor studies demonstrated that this activity is ascribable to carboxyl protease(s). In the presence of dithiothreitol, activity on Azocoll (azo-dye coupled hide powder) was maximal at pH 4.6, 4.6, 3.5 and 5.6 in S. mansoni, D. immitis, Angiostrongylus cantonensis and Ascaris suum respectively. The effects of inhibitors demonstrated that this activity belongs to the thiol protease class. The intraspecific distribution of the protease activities was studied in some of the nematodes from which the organs could be anatomically separated. The distribution patterns of the haemoglobinolytic and azocollytic activities were quite different in An. cantonensis and much the same in As. suum. Based on the present results, acidic haemoglobinolytic activities reported in adult S. mansoni by other authors are thought to be due to carboxyl and thiol protease(s) respectively.

A Multienzyme Network Functions in Intestinal Protein Digestion by a Platyhelminth Parasite

“…The network of clan CA (cathepsin B, L, and C), clan CD (legumain), and aspartic (cathepsin D) proteases functioning in the schistosome gut is remarkably similar to that found in other trematodes, such as Fasciola (48,57) and Paragonimus (58,59), and in the nematodes Ascaris (60,61), Hemonchus (62,63,64), and hookworm (3,4,8). In some cases, cathepsin L predominates versus cathepsin B (Fasciola), but the overall protease profile is strikingly similar.…”

The activity of selected hydrolases of adult female Ascaris suum, Goeze 1782

“…According to Hogan (1980) the intestine of A. suum is not able to digest proteins to a significant extent, and the proteases which are found there are assimilated from the host. According to Maki and Yanagisawa (1986) aminopeptidases are the dominant protein digesting enzymes in the A. suum intestine, although aspartyl and cysteine proteases were also found. The results obtained in the present study are similar to those obtained by these authors and demonstrate that the Ascaris intestine is more able to digest small-molecular compounds, which is indicated by a high activity of aminopeptidases.…”

“…Rupova et al (1984) claim that such enzymes as trypsin, chymotrypsin and enterokinase are absent from the intestine of A. suum; only cathepsins are present there. According to Maki and Yanagisawa (1986), aminopeptidases are the dominant enzymes connected with the process of protein digestion in the intestine of A. suum. Most of the available literature reporting the presence of carbohydrates digesting enzymes (Zenka & Prokopic, 1984;Żółtowska, 1991, 2001Żółtowska & Dmitryjuk, 1998;Dmitryjuk & Żółtowska, 2004) but it is few information regarding the presence of other hydrolases in the intestine, perienteric fluid and muscles of A. suum.…”

Proteolytic enzymes of infective larvae and adults of Trichostrongylus colubriformis and Haemonchus contortus

“…The relative proteinase activity present in extracts from parasites has been shown to vary considerably, depending on the protein substrate used for analysis (Maki and Yanagisawa 1986;Knox and Jones 1990;Young et al 1995) as well as the medium used for isolation or for determination of the activity. The present investigation shows that the presence of phosphates in the incubation medium (which are very often used) may influence the activity of various proteinases, thus making a comparison of the values recorded among various laboratories difficult.…”