Porta R, Esposito C, Gentile V, Mariniello L, Peluso G, Metafora S
Department of Biochemistry and Biophysics, University of Naples, Italy.
Int J Pept Protein Res. 1990 Feb;35(2):117-22. doi: 10.1111/j.1399-3011.1990.tb00245.x.
One of the major proteins secreted from the rat seminal vesicle epithelium, namely SV-IV, was shown to act in vitro as acyl donor and acceptor substrate for transglutaminase from both guinea pig liver and rat anterior prostate secretory fluid. Electrophoretic and chromatographic experiments indicated that the enzyme catalyzed the formation of multiple modified forms of SV-IV. In the absence of small Mr amines, transglutaminase was able to produce at least six different molecular forms of the protein, half of which possessed an Mr higher than that of native SV-IV. These findings suggested that a variable number of intermolecular, and perhaps intramolecular, crosslinks were formed between one or both glutamine residues and one or more lysine residues occurring in the SV-IV polypeptide chain. In addition, at least three modified forms of the protein were produced by transglutaminase in the presence of high concentrations of spermidine, thus indicating the formation of different (gamma-glutamyl)polyamine derivatives of SV-IV. Rabbit uteroglobin and rat anterior prostate secretory protein(s) were also shown to be able to covalently bind spermidine in the presence of the enzyme. The possible biological significance of transglutaminase-mediated modifications of SV-IV, as well as of other proteins occurring in the mammal seminal fluid, are discussed.
大鼠精囊上皮分泌的主要蛋白质之一，即SV-IV，在体外被证明可作为豚鼠肝脏和大鼠前列腺分泌液中转谷氨酰胺酶的酰基供体和受体底物。电泳和色谱实验表明，该酶催化形成了多种修饰形式的SV-IV。在缺乏小分子胺的情况下，转谷氨酰胺酶能够产生至少六种不同分子形式的该蛋白质，其中一半的分子量高于天然SV-IV。这些发现表明，在SV-IV多肽链中一个或两个谷氨酰胺残基与一个或多个赖氨酸残基之间形成了数量可变的分子间交联，或许还有分子内交联。此外，在高浓度亚精胺存在的情况下，转谷氨酰胺酶产生了至少三种该蛋白质的修饰形式，从而表明形成了不同的SV-IV（γ-谷氨酰）多胺衍生物。在该酶存在的情况下，兔子宫珠蛋白和大鼠前列腺分泌蛋白也被证明能够与亚精胺共价结合。本文讨论了转谷氨酰胺酶介导的SV-IV以及哺乳动物精液中其他蛋白质修饰的可能生物学意义。
