Isolation of antitumor proteins abrin-A and abrin-B from Abrus precatorius

Int J Pept Protein Res. 1978 Nov;12(5):311-7. doi: 10.1111/j.1399-3011.1978.tb02902.x.

Abstract

Two toxic proteins were purified from the seeds of Abrus precatorius by DEAE-A 50 and Sepharose 4B chromatography. One of them does not bind on the Sepharose 4B column (Abrin-b) and the other (Abrin-a) is eluted with 0.2 M galactose. The amino acid compositions and tryptic maps of these two proteins were similar, but not identical. The molecular weights estimated by SDS-gel electrophoresis were 67,000 for abrin-b as compared with 65,000 for abrin-a. In the presence of mercaptoethanol, both abrin-a and abrin-b gave rise to two bands. The lethal doses of abrin-a and abrin-b for mice recorded within 48 h were 10 and 25 microgram per kg of body weight respectively. Abrin-a at 0.8 microgram per ml concentration level agglutinated human 0-type erythrocytes, whereas abrin-b showed no such activity. Abrin-a at 5 microgram per ml concentration level agglutinated both the Sarcoma 180 cells and Ehrlich ascites tumor cells, but it required 150 microgram per ml for abrin-b. Both these two proteins at a sublethal dose could inhibit the growth of Ehrlich ascites tumor cells which were injected simultaneously with these proteins. 131I-abrin-a and 131I-abrin-b were able to bind Sarcoma 180 cells, and the binding of abrin-a could be inhibited by lactose, raffinose, galactose and rhamnose, but none of 15 sugars tested inhibited the binding of abrin-b.

MeSH terms

  • Abrin / analysis
  • Abrin / isolation & purification*
  • Abrin / toxicity
  • Amino Acids / analysis
  • Animals
  • Antineoplastic Agents*
  • Carcinoma, Ehrlich Tumor / drug therapy
  • Chromatography, Affinity
  • Chromatography, Ion Exchange
  • Electrophoresis, Polyacrylamide Gel
  • Lethal Dose 50
  • Male
  • Mice
  • Molecular Weight
  • Plant Lectins
  • Plant Proteins / isolation & purification*
  • Protein Binding / drug effects
  • Sarcoma, Experimental / drug therapy
  • Seeds / analysis*
  • Trypsin / pharmacology

Substances

  • Amino Acids
  • Antineoplastic Agents
  • Plant Lectins
  • Plant Proteins
  • Abrin
  • Trypsin