Samel Mari, Tõnismägi Külli, Rönnholm Gunilla, Vija Heiki, Siigur Jüri, Kalkkinen Nisse, Siigur Ene
National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia.
Comp Biochem Physiol B Biochem Mol Biol. 2008 Apr;149(4):572-80. doi: 10.1016/j.cbpb.2007.11.008. Epub 2007 Nov 28.
A new l-amino acid oxidase (LAAO) was isolated from the Central Asian cobra Naja naja oxiana venom by size exclusion, ion exchange and hydrophobic chromatography. The N-terminal sequence and the internal peptide sequences share high similarity with other snake venom l-amino acid oxidases, especially with those isolated from elapid venoms. The enzyme is stable at low temperatures (-20 degrees C, -70 degrees C) and loses its activity by heating at 70 degrees C. Specific substrates for the isolated protein are l-phenylalanine, l-tryptophan, l-methionine and l-leucine. The enzyme has antibacterial activity inhibiting the growth of Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria. N. naja oxiana LAAO dose-dependently inhibited ADP- or collagen-induced platelet aggregation with IC(50) of 0.094 microM and 0.036 microM, respectively. The antibacterial and anti-aggregating activity was abolished by catalase.
通过尺寸排阻色谱、离子交换色谱和疏水色谱从中亚眼镜蛇（Naja naja oxiana）毒液中分离出一种新型L-氨基酸氧化酶（LAAO）。该酶的N端序列和内部肽段序列与其他蛇毒L-氨基酸氧化酶高度相似，尤其是与从眼镜蛇科毒液中分离出的那些酶。该酶在低温（-20℃、-70℃）下稳定，在70℃加热会失去活性。分离出的该蛋白的特异性底物为L-苯丙氨酸、L-色氨酸、L-甲硫氨酸和L-亮氨酸。该酶具有抗菌活性，可抑制革兰氏阳性菌（枯草芽孢杆菌）和革兰氏阴性菌（大肠杆菌）的生长。中亚眼镜蛇LAAO对ADP或胶原诱导的血小板聚集具有剂量依赖性抑制作用，IC50分别为0.094 microM和0.036 microM。过氧化氢酶可消除其抗菌和抗聚集活性。
