Effect of Different Papain Concentrations on the Properties of Chicken Skin Protein Hydrolysates

Chicken skin is a source of animal protein hydrolysate, which has a potential as an antioxidant. This study aimed to determine the effect of different concentrations of the enzyme papain on the degree of hydrolysis, antioxidant capacity, percentage of reducing power (%RP) and amino acid composition of chicken skin protein hydrolysate. Hydrolysis was carried out using papain with various concentrations (3%, 4% and 5%, w/w protein substrate) at pH 7 and 50℃ for 6 h. The degree of hydrolysis was determined by spectrophotometry. Antioxidant capacity and %RP was determined by ferric reducing antioxidant power method and expressed in milligram of ascorbic acid equivalent per gram of sample, and amino acid composition were determined using high-performance liquid chromatography. The results showed that variations in papain concentration had a significant effect (P<0.05) on the degree of hydrolysis, antioxidant capacity and %RP of chicken skin hydrolysate. The papain concentration of 4% resulted in the optimum protein hydrolysate with a degree of hydrolysis of 61.68%±0.64%, an antioxidant capacity of 8.72±0.30 mg AA/g sample and a %RP of 54.12%±1.78%. The protein hydrolysates of the treated chicken skin showed a high content of amino acids, namely, glycine, glutamate, proline, arginine and aspartate.

Restoration of the reduced CLSP activity alleviates memory impairment in Alzheimer disease

Calmodulin-like skin protein (CLSP), a secreted peptide, inhibits neuronal death in cell-based Alzheimer’s disease (AD) models and transgenic overexpression of the CLSP gene suppresses synaptic loss and memory impairment in AD model mice, APPswe/PS1dE9 double transgenic mice (APP/PS1 mice). Despite the anticipated role of CLSP as an AD-suppressing factor, it remains unanswered whether the insufficiency of the CLSP activity is linked to the AD pathogenesis. In this study, we first show that adiponectin, a CLSP potentiator/protector, dominantly determines the CLSP activity in the central nervous system where there are sufficient concentrations of CLSP, higher concentrations of CLSP inhibitors such as apolipoprotein E, and smaller concentrations of adiponectin. We next show that both the levels of brain adiponectin and the intraneuronal levels of SH3BP5, an important effector of the CLSP signal, are reduced in both AD patients and APP/PS1 mice. Finally, the restoration of the CLSP activity by subcutaneous injection of a hybrid peptide named CLSPCOL consisting of CLSP(1-61) and the collagen-homologous region of adiponectin, which has more potent neuroprotective activity than CLSP, is insensitive to the suppression by the CLSP inhibitors, and is efficiently recruited into brains, alleviates dementia and synaptic loss in the aged APP/PS1 mice. Collectively, these results suggest that the reduction in the CLSP activity, likely caused by the reduction in the levels of adiponectin, leads to the insufficient protection of neurons from neurotoxicity in the AD brains and the restoration of the CLSP activity is a promising strategy for the treatment of AD.

Skin Protein-Derived Peptide-Conjugated Vesicular Nanocargos for Selected Skin Cell Targeting and Consequent Activation

Several studies have reported that a drug nanocarrier conjugated with ligands having cell binding ability improves drug delivery performance, but multiple cell-targeting and the resultant activation in designated cells has...

A Comprehensive Review of Alzheimer’s Association with Related Proteins: Pathological Role and Therapeutic Significance

: Alzheimer’s is an insidious, progressive, chronic neurodegenerative disease which causes the devastation of neurons. Alzheimer's possesses complex pathologies of heterogeneous nature counting proteins as one major factor along with enzymes and mutated genes. Proteins such as amyloid precursor protein (APP), apolipoprotein E (ApoE), presenilin, mortalin, calbindin-D28K, creactive protein, heat shock proteins (HSPs), and prion protein are some of the chief elements in the foremost hypotheses of AD like amyloid-beta (Aβ) cascade hypothesis, tau hypothesis, cholinergic neuron damage, etc. Disturbed expression of these proteins results in synaptic dysfunction, cognitive impairment, memory loss, and neuronal degradation. On the therapeutic ground, attempts of developing anti-amyloid, anti-inflammatory, anti-tau therapies are on peak, having APP and tau as putative targets. Some proteins, e.g., HSPs, which ameliorate oxidative stress, calpains, which help in regulating synaptic plasticity, and calmodulin-like skin protein (CLSP) with its neuroprotective role are few promising future targets for developing anti-AD therapies. On diagnostic grounds of AD C-reactive protein, pentraxins, collapsin response mediator protein-2, and growth-associated protein-43 represent the future of new possible biomarkers for diagnosing AD. The last few decades were concentrated over identifying and studying protein targets of AD. Here, we reviewed the physiological/pathological roles and therapeutic significance of nearly all the proteins associated with AD that addresses putative as well as probable targets for developing effective anti-AD therapies.

ISOLATION, CHARACTERIZATION, AND DETERMINATION OF ANTIOXIDATIVE PROPERTIES OF PROTEIN EXTRACTED FROM ROHU (LABEO ROHITA) FISH SKIN

Objective: Isolation, characterization and analysis of antioxidant activity of protein extracted from Labeo rohita skin. Methods: The present work aimed to characterize protein isolated from Indian major carp L. rohita skin. Protein isolation was carried out by the salting-out method and the protein content was estimated with bovine serum albumin. Isolated protein was subjected to Fourier-transform infrared analyzer to identify the presence of –NH3 group to be claimed as protein. It was also subjected to high-performance liquid chromatography (HPLC) analyzer and run against standard collagen (Sigma), the molecular weight of the protein was determined through mass spectroscopy (MS) to know the protein structure more precisely the protein isolate was studied under a scanning electron microscope (SEM). Antioxidative activity of the crude protein sample was studied through 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant potential (FRAP) assay, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. Results: The protein isolated was 23% of the dry weight of fish skin. In HPLC analysis, the isolated protein gives peaks that are similar to that of standard collagen, and in MS, its molecular weight was near about 300 kDa, which is the molecular weight of collagen type 1. The SEM image shows a crystal structure of protein isolates. Results of antioxidative property show that fish skin protein isolates have good antioxidative activity also. Conclusion: The isolated protein was collagen and it can be used as a replacer of the renowned market available collagen.

Study on the Kinetics of Salmon Skin Proteolysis

In this study, in order to study the kinetic mechanism of enzymatic hydrolysis of salmon protein, the kinetic model of enzymatic hydrolysis of salmon skin protein by papain was established. The skin protein of salmon was hydrolyzed by papain under the following conditions: the mass concentration of salmon skin protein is 55 g/L, the initial papain concentration is 2.0 g/L, the pH of enzymatic solution is 7.2 and the temperature of enzymatic hydrolysis is 55 °C. Finally, the kinetic model of hydrolysis was established as follows: Hydrolysis rate R =(27.217E0–0 0357S0exp[–0.2587(DH)]; Degree of hydrolysis DH = 3.879 ln[1 + 7.0165E0/S0 –0.0092t]. The reaction rate constant k3 = 27.217 min–1 and the enzyme deactivation constant kd = 7.0752 min–1 were deduced to control the enzymatic hydrolysis process. Further verification tests showed that the theoretical value of the degree of hydrolysis of the model was basically consistent with the actual value, and the kinetic model had certain practical value, indicating that the established salmon skin protease kinetic model could be used to guide and optimize the enzymatic hydrolysis process.