Jacob Nicemol, Asha Poorna C, Prema P
Biotechnology Division, National Institute for Interdisciplinary Science and Technology (CSIR), Trivandrum 695019, India.
Bioresour Technol. 2008 Sep;99(14):6697-701. doi: 10.1016/j.biortech.2007.10.002. Epub 2007 Nov 8.
Polygalacturonase produced by Streptomyces lydicus was purified to homogeneity by ultrafiltration and a combination of ion exchange and gel filtration chromatographic procedures. The purified enzyme was an exo-polygalacturonase with a molecular weight of 43 kDa. It was optimally active at 50 degrees C and pH 6.0. The enzyme was stable from pH 4.0 to 7.0 and at or below 45 degrees C for 90 min. K(m) value for polygalacturonic acid was 1.63 mg/mL and the corresponding V(max) was 677.8 microM min(-1) mg(-1). The inhibition constant (K(i)) for gluconic acid d-lactone was 20.75 mM. Purified enzyme had been inhibited by N-bromosuccinimide, while l-tryptophan could induce enzyme activity, indicating the involvement of tryptophan at the active site.
利迪链霉菌产生的聚半乳糖醛酸酶通过超滤以及离子交换和凝胶过滤色谱程序的组合被纯化至同质。纯化后的酶是一种分子量为43 kDa的外切聚半乳糖醛酸酶。它在50℃和pH 6.0时具有最佳活性。该酶在pH 4.0至7.0以及45℃或更低温度下90分钟内稳定。聚半乳糖醛酸的K(m)值为1.63 mg/mL，相应的V(max)为677.8 microM min(-1) mg(-1)。葡萄糖酸δ-内酯的抑制常数（K(i)）为20.75 mM。纯化后的酶被N-溴代琥珀酰亚胺抑制，而L-色氨酸可诱导酶活性，表明色氨酸参与了活性位点。
