title: Purification and properties of a monomeric lactate dehydrogenase from yak Hypoderma sinense larva.
abstract: The objective of the present study was to study the characteristics of lactate dehydrogenase (LDH) from Hypoderma sinense larva. H. sinense larvae were collected from yak (Bos grunniens) and identified by a PCR-RFLP method. Analysis of LDH activity showed that the total LDH activity in H. sinense larva was negatively correlated with the length of larva. Polyacrylamide gel electrophoresis of the extracts of H. sinense larvae revealed one band of LDH, which was then purified by affinity chromatography and gel filtration. This enzyme showed an approximately 36 kDa band on SDS-gel under both reducing and non-reducing conditions, in addition, size exclusion chromatography analysis showed that its molecular weight was smaller than bovine serum albumin (67 kDa), indicating that it contains only one subunit. Michaelis constants (Km) values assay revealed that LDH from H. sinense larva showed significantly lower Km for lactate than other animals. LDH of H. sinense larva was stable at 60 °C for 15 min, and also exhibited high catalytic efficiency in a wide range of pH. HgCl₂ at the concentration of 0.1mM significantly decreased the activity of LDH from H. sinense larva but not at the concentration of 0.01 mM. The results of the present study demonstrate that LDH from H. sinense larva is a thermal stable and pH insensitive enzyme suitable for catalyzing both forward and reverse reactions.
authors.affiliation: College of Life Science and Technology, Southwest University for Nationalities, Chengdu, Sichuan 610041, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.forename: Suyu
authors.initials: S
authors.lastname: Jin
authors.forename: Lin
authors.initials: L
authors.lastname: Huang
authors.forename: Haohao
authors.initials: H
authors.lastname: Liu
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Huang
authors.forename: Yaqiu
authors.initials: Y
authors.lastname: Lin
authors.forename: Yucai
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology*; D002681:China; D002846:Chromatography, Affinity / Q000662:veterinary; D002850:Chromatography, Gel / Q000662:veterinary; D004175:Diptera / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D007814:Larva / Q000145:classification / Q000201:enzymology / Q000235:genetics; D008627:Mercuric Chloride / Q000494:pharmacology; D008970:Molecular Weight; D009198:Myiasis / Q000469:parasitology / Q000662:veterinary*; D009243:NAD / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D011773:Pyruvates / Q000378:metabolism; D013696:Temperature
chemical_list: D007527:Isoenzymes; D011773:Pyruvates; D009243:NAD; D019344:Lactic Acid; D008627:Mercuric Chloride; D007770:L-Lactate Dehydrogenase