Primary structure of p-momorcharin, a ribosome-inactivating protein from the seeds of Momordica Charantia Linn (Cucurbitaceae)

The complete amino acid sequence of β-momorcharin, a ribosome-inactivating protein from the seeds of Momordica charantia Linn (Cucurbitaceae) has been determined. This has been done by the sequence analysis of peptides obtained by enzymatic digestion with trypsin, chymotrypsin and S. aureus V8 protease, as well as by chemical cleavage with BNPS-skatole. The protein consists of 249 amino acid residues containing one asparagine - linked sugar group attached to the site of Asn 5 1 and has a calculated relative molecular mass of 28,452 Da without addition of the carbohydrate. Comparison of this sequence with those of trichosanthin and other ribosome-inactivating proteins from different species of plants shows a significant homology with each other. Regarding the similarity of their biological properties, an active domain of these proteins has been predicted here.     

Immunoaffinity purification of α-momorcharin from bitter melon seeds (Momordica charantia)

α‐Momorcharin (α‐MMC), a type I ribosome‐inactivating protein (RIP), has shown therapeutic potential such as anti‐tumor and anti‐viral agent. Traditional process of α‐MMC purification from bitter melon seeds was time consuming and low efficient. To take this challenge, we made an affinity matrix by coupling the monoclonal antibody (McAb) with Sepharose 4B. Using this attractive strategy, 196 mg of α‐MMC was obtained from 100 g of bitter melon seeds as the starting material. The yield of the protein was 2.7%. The homogeneity and properties of the protein were assessed by SDS‐PAGE, acidic PAGE, RP‐HPLC and N‐terminal sequence as well as Western blot. Purified α‐MMC showed remarkable inhibition to the melanoma cell line JAR and EMT‐62058. In addition, it also displayed obvious inhibition on hepatitis B virus (HBV). This work provided a simple, rapid and efficient approach for α‐MMC purification from Momordica charantia.     

Primary structure of β-momorcharin,a ribosome-inactivating protein from the seeds of Momordica Charantia Linn (Cucurbitaceae)

The complete amino acid sequence of β-momorcharin, a ribosome-inactivating protein from the seeds of Momordica charantia Linn (Cucurbitaceae) has been determined. This has been done by the sequence analysis of peptides obtained by enzymatic digestion with trypsin, chymotrypsin and S.aureus V8 protease, as well as by chemical cleavage with BNPS-skatole. The protein consists of 249 amino acid residues containing one asparagine - linked sugar group attached to the site of Asn 51 and has a calculated relative molecular mass of 28,452 Da without addition of the carbohydrate. Comparison of this sequence with those of trichosanthin and other ribosome-inactivating proteins from different species of plants shows a significant homology with each other. Regarding the similarity of their biological properties, an active domain of these proteins has been predicted here.