Anti-M. tuberculosis Polyclonal antibody[HRP]

Tuberculosis (TB) is a globally significant infective disease that is caused by a single infectious agent, Mycobacterium tuberculosis (Mtb). Because of the rise in the number of multidrug-resistant (MDR) TB strains, identification of alternative drug targets for the development of drugs with different mechanism of actions is desired. CYP121A1, one of the twenty cytochrome P450 enzymes encoded in the Mtb genome, was previously shown to be essential for bacterial growth. This enzyme catalyzes the intramolecular C-C crosslinking reaction of the cyclopeptide cyclo(L-tyr-L-tyr) (cYY) yielding the metabolite mycocyclosin. In the present study, acetylene-substituted cYY-analogs were synthesized and evaluated as potential mechanism-based inhibitors of CYP121A1. The acetylene-substituted cYY-analogs were capable of binding to CYP121A1 with affinities comparable with cYY, and exhibited a Type I binding mode, indicative of a substrate-like binding, mandatory for metabolism. Only the cYY-analogs which contain an acetylene-substitution at one (2a) or both (3) para-positions of cYY showed mechanism-based inhibition of CYP121A1 activity. The values of K-1 and k(mact) were 236 mu M and 0.045 min(-1), respectively, for compound 2a, and 145 mu M and 0.015 min(-1), repectively, for compound 3 The inactivation could neither be reversed by dialysis nor be prevented by including glutathione. LC-MS analysis demonstrated that the inactivation results from covalent binding to the apoprotein, whereas the heme was unmodified. Interestingly, the mass increment of the CYP121A1 apoprotein was significantly smaller than was expected from the ketene formed by oxidation of the acetylene-group, indicative for a secondary cleavage reaction in the active site of CYP121A1. Although the two acetylene-containing cYY-analogs showed significant mechanism-based inhibition, growth inhibition of the Mtb strains was only observed at millimolar concentrations. This low efficacy may be due to insufficient irreversible inactivation of CYP121A1 and/or insufficient cellular uptake. Although the identified mechanism-based inhibitors have no perspective for Mtb-treatment, this study is the first proof-of-principle that mechanism-based inhibition of CYP121A1 is feasible and may provide the basis for new strategies in the design and development of compounds against this promising therapeutic target.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis and is an endemic disease in Sudan, where it has rapidly become the major complication of human immunodeficiency virus (HIV) infection. Thus, this study aimed to determine the prevalence of HIV among TB patients and evaluate the co-infection rate. The association of HIV prevalence with gender, age, and duration of treatment as risk factors was also determined. A descriptive cross-sectional study was performed in Omdurman Abu Anga Hospital, Khartoum, Sudan, from October 2018 to March 2019. A total of 281 blood samples were obtained randomly from pulmonary TB patients. The plasma was examined for the presence of HIV antibodies using sandwich ELISA. A structured questionnaire was used during data collection. A noticeable marker for HIV immunoglobulin M/immunoglobulin G was found in 12 patients (4.3%), of which five patients (41.7%) were diagnosed as new TB cases. Moreover, the relationship between age, sex, and duration of TB treatment and the prevalence of HIV was not significantly different (P > 0.05). In conclusion, the prevalence of HIV antibodies among TB pulmonary patients is high. Therefore, all TB patients should be examined for HIV risk factors and advised to undergo HIV testing. Further studies are essential to provide more insights into the epidemiology of the co-infection to better report the double burden of HIV and TB among TB patients in Sudan.