Melbye S W, Brant B A, Freedberg I W
Br J Dermatol. 1977 Oct;97(4):355-64. doi: 10.1111/j.1365-2133.1977.tb14242.x.
Sodium acetate and sulphuric acid extracts of human epidermis can each be separated by chromatographic techniques into three or more fractions with ribonuclease activity. Eight of these fractions were compared with respect to molecular weight, pH activity profile, polyribonucleotide hydrolysis, and activity in the presence of low levels of spermidine. Sodium acetate and sulphuric acid extracts were also prepared from callus and from psoriatic lesions and compared with extracts from normal epidermis for their response to exogenous spermidine. All eight human epidermal ribonuclease fractions studied had an apparent molecular weight of 15,000 daltons. Seven of the ribonuclease fractions were optimally active at alkaline pHs (pH 7.3-7.6 in sodium phosphate and pH 8.I in Tris-HCl) while the eighth ribonuclease was most active at pH 5.6 in a citrate-phosphate buffer. All enzymes hydrolyzed polycytidylic acid and five also hydrolyzed polyuridylic acid. None hydrolyzed polyadenylic acid. Seven of the eight ribonucleases studied exhibited greater activity in the presence of added spermidine. The extracts from psoriatic scales showed markedly elevated ribonuclease levels which could not be raised further by the addition of spermidine.
人表皮的醋酸钠提取物和硫酸提取物均可通过色谱技术分离成三个或更多具有核糖核酸酶活性的组分。对其中八个组分在分子量、pH活性谱、多聚核糖核苷酸水解以及低水平亚精胺存在下的活性方面进行了比较。还从愈伤组织和银屑病皮损中制备了醋酸钠提取物和硫酸提取物，并将其与正常表皮提取物对外源亚精胺的反应进行了比较。所研究的所有人表皮核糖核酸酶组分的表观分子量均为15,000道尔顿。七个核糖核酸酶组分在碱性pH值下（在磷酸钠中pH为7.3 - 7.6，在Tris - HCl中pH为8.1）活性最佳，而第八个核糖核酸酶在柠檬酸盐 - 磷酸盐缓冲液中pH为5.6时活性最高。所有酶均能水解聚胞苷酸，其中五种还能水解聚尿苷酸。无一能水解聚腺苷酸。所研究的八个核糖核酸酶中有七个在添加亚精胺时表现出更高的活性。银屑病鳞屑提取物显示核糖核酸酶水平明显升高，添加亚精胺后无法进一步提高。
