The kinetic characteristics, of interaction between hK6 (human Kallikrein) and soybean (BBI), protease inhibitor and antitumor agent, in the presence of substrate (Phenylalanine –Serine-Arginine)-(7-amino-4- methyl-coumarin) (FSR-AMC) were investigated. The hK6 were found to bind soybean in two reversible steps, by slow binding inhibition mechanism. The Ki of the first step binding was 13 nM and Ki* of the second binding step was 1.6 nM. The microcopic rate constants were calculated as follows: 311 M-1.S-1 for k3 , 0.04×10-6 M-1.S-1 for k –3 , 0.2×10-6 S-1 for k 4 and 0.025×10-6 S-1 for k-4 respectively. The results suggested that the interaction mechanism between hK6 and soybean was like that of trypsin with this inhibitor but with rather lower inhibitory constants values.

Dear Editor, Curcumin is a natural product of Curcuma longa L (turmeric) plant, which has remarkable roles in various biological fields and its properties consist of antioxidant and anti-inflammatory activity, anti-arthritic and anti-diabetic effects, lipid metabolism, protective role against cardiovascular diseases and ischemia, and the regulation of neural process (1). Recently, it has been suggested about the potential effects of Curcumin against pathogenic microorganisms such as bacteria, fungi, and viruses (2). According to the literature, Curcumin has anti-viral effects on virulent viruses such as HIV, HTLV-1, HBV, HCV, HPV, HSV, JEV, influenza, and Coxsackievirus. Although this yellow chemical could be taken into account as a unique antiviral herbal drug, especially for enveloped viruses, it has no toxic effects on the human cell-line viability. Moreover,

Background: Drug resistance is emerging as one of the greatest challenges in the development of effective treatment for HIV infection. The importance of clinical studies in this field stems from the world wide growing of treatment drug-resistant mutations. Objectives: This study was performed to determine the HIV subtype and the resistance mutations to the protease inhibitors in both untreated HIV patients and patients under treatment with protease inhibitors (PIs) in Iran. Methods: The study was conducted on two groups of participants. The first group consisted of 25 HIV patients who did not receive any antiretroviral treatment. The second group included 25 HIV patients who have being treated with a combination of protease inhibitors. After genome extraction, a nested polymerase chain reaction was performed to amplify the protease gene. Upon confirmation using electrophoresis, the amplicons or PCR products were sequenced and analyzed to determine the drug resistance mutations as well as the viral subtypes. Results: Nomutations were found in the first group; however, 32% of the samples in the second group had PI related drug-resistance mutations. The major mutations were V82A and M46I, which were seen in 12% of the samples, while the minor mutation F53L was seen in 16% of the samples. The subtype analysis showed that 94% of the samples were subtype CRF35_AD, and 6% were of defined as subtype A. Conclusions: The present study reports updates on the mutations related to protease resistance in Iranian HIV patients receiving treatment. Our data, as well as existing reports, support the need for the optimization of treatment to prevent emergence of resistant viruses and a search for new antiretroviral drug candidates for HIV patients.

The aim of the present work was to purify cysteine protease inhibitors from rapeseed (Brassica napus L.), with potential activity on digestive protease of Colorado Potato Beetle (CPB), Leptinotarsa decemlineata (Say). Ammonium sulfate precipitated proteinaceous fractions; 30, 50, 70, and 100% showed 39.07, 57.03, 51.47, and 22.44% inhibition on the fourth instar larval gut general protease activity, respectively. Fraction 50% showed the highest inhibitory effect on digestive general protease activity of all developmental stages.Gel assays approved the inhibition of the enzyme activity. Fraction 50% was purified by using various chromatography techniques; ion-exchange using DEAE, gel filtration and affinity using SiO2-CPB larval gut homogenate. Three peaks of protein were eluted from ion exchange chromatography using NaCl step gradient, also from gel filtration chromatography. When Z-Ala-Arg-Arg-4mbNA was used as cysteine protease substrate, the purification fold of second fraction of ion exchange chromatography was obtained 24.80, also the yield was 59.09%, the third fraction of gel permeation resulted in a 25.60 fold purification with 28.53% of recovery, and the fraction of affinity chromatography obtained a 22.72 fold purification and yielded 36.35%. In the SDS-PAGE, apparent molecular mass of purified proteins were 34 and 32 kDa by ion-exchange and 24 and 22 kDa by affinity. However, gel filtration was not an appropriate method in this study, because the purified protein band (s) were not observed on the gel. Consequently, these chromatography methods were appropriate methods to purification of inhibitor cystatins, specially affinity which was prepared by using CPB gut enzyme as ligand and obtained specific inhibitor proteins of CPB gut protease activity.

Introduction: Long-term storage of seeds under unfavorable conditions leads to their deterioration associated with decreased germination. Several studies have shown increased lipolysis in deteriorating seeds, but little is known about the role of protease activity during deterioration. In the present study, the effect of the controlled deterioration (CD) on the mobilization of storage proteins and the effects of pretreatment with protease inhibitor (PMSF) on the germination percentage of walnut kernels after CD were investigated. Materials and methods: Kernels were adjusted to 15% and 20% MC with water (control) or PMSF solution and then incubated for 3 and 6 days at 45°C for CD. Results: CD increased soluble proteins, solubility of 19-24 kDa glutelins, increased activity of a 80 kDa protease, accumulation of total amino acid, proline and increased protein carbonylation. Although aging-dependent decrease of germination was similar in both control and PMSF pretreatment, the aged kernels in PMSF pretreatment had lower proline, amino acid and carbonyl groups contents compared to the control. Discussion: These results suggest that CD causes increased solubility of protein reserves, but the inhibition of serine protease(s), unlike lipase, has no effect on improving the adverse physiological effects of CD including germination loss, and only at the biochemical level, it partially improved kernel response to stress. Identification of different metabolic pathways operating during CD of kernels can draw a picture of deterioration mechanism and also leads to introducing protocols for the quality and viability maintenance of kernels during storage.