Girish K S, Shashidharamurthy R, Nagaraju S, Gowda T V, Kemparaju K
Department of Biochemistry, University of Mysore, Manasagangotri, Mysore 570 006, India.
Biochimie. 2004 Mar;86(3):193-202. doi: 10.1016/j.biochi.2004.02.004.
Hyaluronidase, ubiquitous enzyme in snake venoms, known originally as "spreading factor", has not been well studied. The present study describes the purification and characterization of hyaluronidase from Indian cobra (Naja naja) venom and provides systematic evaluation of the spreading property of the enzyme. Hyaluronidase (NNH1) has been purified through gel permeation and ion exchange chromatography. The molecular mass was found to be 70.406 kDa by MALDI-TOF mass spectrometry and with the (p)i pI of 9.2. The amino acid sequence of the N-terminus was found to be NEQSTHGAYV. The enzyme shows absolute specificity for hyaluronan and belongs to the group of neutral active enzymes. Tetrasaccharides are the final product of hyaluronan digestion. The enzyme cleaves beta 1,4-glycosidic linkage and belongs to a group of endo-beta-N-acetyl hexosaminidases. Hyaluronidase indirectly potentiates the myotoxicity of VRV-PL-VIII, a phospholipolytic myotoxin, and also the hemorrhagic potency of a hemorrhagic complex-I. Localization of hyaluronan in human skin section and selective degradation by venom hyaluronidase (NNH1) corroborate the plausible in vivo degradation of hyaluronan in the extracellular matrix (ECM) resulting in easy dissemination of VRV-PL-VIII myotoxin and hemorrhagic complex-I.
透明质酸酶是蛇毒中普遍存在的一种酶,最初被称为“扩散因子”,目前尚未得到充分研究。本研究描述了从印度眼镜蛇(Naja naja)毒液中纯化透明质酸酶并对其进行表征,并对该酶的扩散特性进行了系统评估。透明质酸酶(NNH1)已通过凝胶渗透和离子交换色谱法纯化。通过基质辅助激光解吸电离飞行时间质谱法测定其分子量为70.406 kDa,等电点(p)i为9.2。发现其N端氨基酸序列为NEQSTHGAYV。该酶对透明质酸具有绝对特异性,属于中性活性酶类。四糖是透明质酸消化的终产物。该酶能切割β-1,4-糖苷键,属于内切β-N-乙酰己糖胺酶类。透明质酸酶间接增强了磷脂分解性肌毒素VRV-PL-VIII的肌毒性,以及出血复合物-I的出血效力。透明质酸在人体皮肤切片中的定位以及毒液透明质酸酶(NNH1)对其的选择性降解,证实了透明质酸在细胞外基质(ECM)中可能发生的体内降解,从而导致VRV-PL-VIII肌毒素和出血复合物-I易于扩散。