Cocuzzi E T, Chung S I
J Biol Chem. 1986 Jun 25;261(18):8122-7.
Transglutaminase in the rat lung is tightly associated with the insoluble matrix which is not extractable with detergent, 0.5 M NaCl, and 40% glycerol solutions. The insoluble matrix was found to be rich in heparin sulfate and poor in collagen, elastin, and DNA. The lung transglutaminase was found to be distinct from tissue transglutaminase (identifiable with the well-characterized guinea pig liver transglutaminase) in its retention volume in DEAE-Sephacel columns and its Kd value in gel-filtration columns. The enzyme was activated 6-8-fold with the sulfhydryl reagent dithiothreitol. This activation was accompanied with the dissociation of enzyme from the tightly bound insoluble matrix and resulted in changes of the molecular properties of the enzyme--increase in affinity for anion-exchanger and decrease in Stokes radius. Addition of 50 mM KSCN induced a 2-fold increase in SH-dependent activation of transglutaminase activity. These results suggest that sulfhydryl agents may play a role in the activation and compartmental translocation of the transglutaminase in the lung.
大鼠肺中的转谷氨酰胺酶与不溶性基质紧密结合，该基质不能用去污剂、0.5M氯化钠和40%甘油溶液提取。发现不溶性基质富含硫酸乙酰肝素，而胶原蛋白、弹性蛋白和DNA含量较低。在DEAE-葡聚糖凝胶柱中的保留体积和凝胶过滤柱中的Kd值方面，发现肺转谷氨酰胺酶与组织转谷氨酰胺酶（可通过特征明确的豚鼠肝脏转谷氨酰胺酶鉴定）不同。该酶被巯基试剂二硫苏糖醇激活6-8倍。这种激活伴随着酶从紧密结合的不溶性基质中解离，并导致酶分子性质的变化——对阴离子交换剂的亲和力增加，斯托克斯半径减小。添加50mM硫氰酸钾会使转谷氨酰胺酶活性的巯基依赖性激活增加2倍。这些结果表明，巯基试剂可能在肺中转谷氨酰胺酶的激活和区室转运中起作用。
