Two　proteins　of　similar　molecular　weight　(named　as　ASPR-C-1　and　ASPR-C-2)　from　the　crude　drug　of　Angelica　sinensis　were　purified　and　characterized　by　80%　ammonium　sulfate　precipitation,　Sephadex　G-50　gel　filtration　chromatography,　and　DEAE-Sepharose　anion　exchange　chromatography.　The　molecular　weight　of　ASPR-C-1　and　ASPR-C-2　on　SDS-PAGE　was　17.33　kDa　and　17.18　kDa,　respectively.　They　were　mainly　monomeric　in　solution,　but　partially　formed　dimers　and　they　were　glycoproteins　with　glycosyl　content　of　2.6%　and　8.2%,　respectively.　Both　ASPR-C-1　and　ASPR-C-2　were　identified　to　be　members　of　pathogenesis-related　10　family　of　proteins　by　matrix-assisted　laser　desorption　ionization　time-of-flight　mass　spectrometry　and　have　ribonuclease　activities　with　the　specific　activity　of　73.60　U/mg　and　146.76　U/mg,　respectively.　The　optimum　pH　of　the　two　isoforms　was　similar,　at　about　5.6,　while　their　optimum　temperatures　were　different.　The　optimum　temperature　of　ASPR-C-1　was　50　℃,　and　that　of　ASPR-C-2　was　60　℃.　Both　isoforms　presented　highest　thermal　stability　at　60　℃.　However,　ASPR-C-2　was　more　thermotolerant　than　ASPR-C-1.　The　latter　was　rapidly　inactivated　and　retained　only　about　20%　residual　activity　while　the　former　still　maintained　about　80%　of　its　original　activity　at　a　higher　treatment　temperature　(80　to　100　℃).　In　addition,　Fe2+　had　an　activating　effect　on　the　ribonuclease　activities　of　two　isoforms　while　Ca2+,　Mg2+,　Zn2+,　Mn2+,　Ag+,　Cu2+,　EDTA　(Elhylene　diamine　tetraacetic　acid),　dithiothreitol　and　sodium　dodecylsulphate　showed　different　degrees　of　inhibition　of　the　enzyme　activities.　Our　findings　provide　a　foundation　for　further　research　on　the　biological　function　of　PR-10　protein　from　Angelica　sinensis.　©　2019,　Science　Press.　All　right　reserved.