title: Inhibition of specific degradation of 57-kDa protein in royal jelly during storage by citrate buffer.
abstract: We have previously shown that ethylenediaminetetraacetic acid (EDTA) suppresses the storage-dependent degradation of 57-kDa protein, which is a possible marker for freshness and quality of royal jelly (RJ) through the inhibition of a proteinase in RJ. We suggested that EDTA could be useful as a preservative agent to maintain the quality of RJ. Here, we report the effects of other metal chelators, di- or tricarboxylic acids such as citric acid and malic acid, on proteinase activity in RJ and the specific degradation of 57-kDa protein during storage. Various carboxylic acids inhibited the proteinase activity in RJ, but did not suppress storage-dependent degradation of 57-kDa protein. However, when RJ was stored with various carboxylate buffers (pH 4.0) at 40 degrees C, the degradation of 57-kDa protein during storage was suppressed through the inhibition of proteinase in RJ. Among the buffers, citrate buffer (pH 4.0) effectively inhibited the decrease of 57-kDa protein concentration in RJ during storage. These results suggest that citrate buffer (pH 4.0) could be available as a new preservative agent to maintain the quality of RJ.
authors.affiliation: Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Kosugi, Toyama 939-0398, Japan. kamakura@pu-toyama.ac.jp
authors.forename: Masaki
authors.initials: M
authors.lastname: Kamakura
authors.forename: Makoto
authors.initials: M
authors.lastname: Fukushima
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Iso
mesh_terms: D000818:Animals; D001516:Bees; D002021:Buffers; D019343:Citric Acid / Q000494:pharmacology*; D004355:Drug Stability; D004492:Edetic Acid / Q000494:pharmacology; D005227:Fatty Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007301:Insect Hormones; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism; D011310:Preservatives, Pharmaceutical; D011480:Protease Inhibitors / Q000494:pharmacology*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D000099219:Royal Jelly
chemical_list: D002021:Buffers; D019343:Citric Acid; D004492:Edetic Acid; D005227:Fatty Acids; D007301:Insect Hormones; D010447:Peptide Hydrolases; D011310:Preservatives, Pharmaceutical; D011480:Protease Inhibitors; D011506:Proteins; D000099219:Royal Jelly