Some enzymatic properties of Acid phosphatase in the logarithmic and stationary phase of Leishmania major

Leishmania is an obligate intracellular parasite that causes a wide range of disease. This parasite is transmitted via bite of infected sandflies.and has promastigote form in sandfly. Promastigote form has two phase: none virulence logarithmic and virulence stationary phase. According to the accumulation of acid phosphatase (ACP) in stationary phase and its role in the virulence of the parasite, in this study the properties, km and Vm of ACP enzyme were measured in two logarithmic and stationary phases. The present study is a cross sectional study. To culture promastigotes, L.major(MRHO/IR/75/ER) from previously infected Balb/c mice were transferred to medium. Growth curve was generated by daily counting of the parasites and based on this curve logarithmic and stationary phases were divided. Frozen promastigotes of each stage with sodium acetate and Triton-X-100 were homogenized and ACP was measured by calorimetric assay. Logarithmic and stationary parasites were collected in the fourth and seventh days respectively. The rate of ACP activity was determined: 0.9 ± 0.03 in logarithmic and 1.18 ± 0.01 µM/min/mgprotein in stationary phases. Also Vm of this enzyme was 75.76 ± 0.57 in logarithmic and 98/04 ± 0.96 in stationary phases and Km was determined 142.93 ± 4.08 µM and 106.39± 1.14 µM in logarithmic and stationary phase respectively (P<0.05). In stationary promastigotes the rate of ACP activity and Vm were 23% higher and Km was 28% lower than in logarithmic phase. Changes in the properties of ACP is probably one of the essential factors for parasites to attack the macrophages and these variations are very important parameters in virulence of promastigotes.