Partial characterization of digestive proteases of the three-spot cichlidCichlasoma trimaculatum(Günter 1867)

Abstract

Partial characterization of digestive proteases in the threespot cichlid Cichlasoma trimaculatum juveniles was conducted. It was determined that there is higher alkaline proteases activity (3.95 AE 0.32 IU mg À1 protein) compared to acidic proteases (2.01 AE 0.57 IU mg À1 protein). Optimal temperature for alkaline proteases is 60°C which resulted in more thermostability to temperature changes. On the other hand, optimal temperature for acidic proteases is 50°C. Optimal pH for acidic proteases was pH 2, while for alkaline proteases, it was pH 10, which resulted in more stability in relation to pH changes than acidic protease. The use of specific inhibitors and the SDS-PAGE electrophoresis analysis revealed seven types of bands for alkaline proteases, which make evident the main presence of serine proteases. In acidic proteases, more than 98 g kg À1 of the activity was inhibited with pepstatin A inhibitor. Therefore, it is evident that C. trimaculatum digestion is composed by acidic and alkaline proteases; thus, it should be considered an omnivorous fish.

Partial Characterization of Digestive Proteases in the Green Cichlid, Cichlasoma beani

“…Of these, the group of serine proteases was inhibited by 60% by Phenyl methyl sulphonyl fluoride (PMSF), and by 88% and 57% with ovalbumin and soybean trypsin inhibitor (SBT1), respectively. This pattern in which serine proteases were more markedly affected than the rest of the enzymes was similar to findings in S. aequifasciata [28], T. thynnus [17], C. idella [36] and C. trimaculatum [8]. The other enzyme group subject to high metal inhibition was that of the proteases, with 87% inhibition by Phenanthroline and 55% by ethyl-diamine tetra-acetic acid (EDTA).…”

“…Usually, the difference between the optimum temperatures of alkaline and acid proteases have been described in carnivorous fish species such as T. thynnus [17], B. orbignyanus [26] and P. maculatofasciatus [33]. The optimum temperature of acid proteases in C. beani was 55 • C, comparable to that described in the hybrid O. niloticus × O. aureus [37], but higher than that found for S. senegalensis [19], T. orientalis [35] and C. trimaculatum [8], with temperature optima from 35 to 55 • C. The activity of acid proteases is stable up to 45 • C, resulting in values >100% for some of the incubation times, but over 60% of the activity is lost above 55 • C. This could be due to denaturation of pepsin at temperatures >55 • C, in agreement with results described by [32]. In contrast, alkaline proteases have an optimal temperature of 65 • C, which is greater than that reported for the crevalle jack Caranx hippos, spotted goatfish Pseudupeneus maculatus, parrotfish Sparisoma sp., trahira Hoplias malabaricus [40] and O. niloticus [20], species that show an optimum temperature ranging from 50 to 55 • C. The high thermostability of the alkaline proteases in C. beani is similar to that reported for C. undecimalis [16], A. tropicus [24] and C. trimaculatum [25].…”

“…Prior studies examined the effects of stocking density on growth and survival of this species under culture conditions [4,5]. There are currently no studies on biochemistry and digestive physiology of this species, although studies have been conducted on digestive biochemistry in species of the genus Cichlasoma [6][7][8], which contribute…”

Partial characterization of digestive proteases in sheepshead, Archosargus probatocephalus (Spariformes: Sparidae)

“…On the other hand, the optimum temperature in A. probatocephalus alkaline proteases is 10 °C higher at the optimum temperature of the acid proteases and at the same time shows more thermostability. In general, this difference between the optimal temperatures of alkaline and acid proteases has been described in species such as T. thynnus (Essed et al, 2002), B. orbignyanus (García-Carreño et al, 2002) and C. trimaculatum (Toledo-Solís et al, 2016). The optimum temperature of acid proteases was observed as 45 °C, being similar to that reported for S. aurata (Alarcón et al, 1998) and T. orientalis (Matus-De la Parra et al, 2007), which shows a decrease in activity at temperatures from 55 °C, an effect related to the denaturation of pepsin (Nalinanon et al, 2008).…”

“…(Nalinanon et al, 2008), T. alalunga and skipjack tuna Katsuwonus pelamis (Linnaeus, 1758) (Nalinanon et al, 2010a, b) and C. undecimalis (Concha-Frias et al, 2016). On the other hand, the alkaline proteases of sheepshead show an optimum pH of 9, which is common in many species, with maximum activity occurring between pH 9 and 10, as reported in Brycon orbignyanus (García-Carreño et al, 2002), Labeo rohita (Hamilton, 1822) and H. molitrix (Kumar et al, 2007), T. orientalis (Matus-De la Parra et al, 2007), grass carp Ctenopharyngodon idella (Valenciennes, 1844) (Liu et al, 2008), hybrid juvenile tilapia Oreochromis niloticus (Linnaeus, 1758) x Oreochromis aureus (Steindachner, 1864) (Jun-Sheng et al, 2006), D. puntazzo (Tramati et al, 2005), C. urophthalmus (Cuenca-Soria et al, 2014) and Amphilophus trimaculatus (Günther, 1867) ( Toledo--Solís et al, 2016). Nevertheless, species with more than one optimum pH value have been reported, such as C. undecimalis, showed optimal activity at pH 7 and 11 (Con-cha-Frías et al, 2016) that can be attributed to the diversity of enzymes and isoforms present in the species .…”