TITLE Protease activities before and after germination of garlic (Allium sativum L.) bulbs
AUTHOR Yaw-Huei Lin
Institute of Botany, Academia Sinica, Taipei, Taiwan 115, Republic of China
Wen-Hsiang Yao
Institute of Botany, Academia Sinica, Taipei, Taiwan 115, Republic of China
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ABSTRACT When casein was used as a substrate, garlic bulbs had lower proteinase activity levels before germination than after. The opposite was observed with hemoglobin as the substrate. Before germination, when 4-nitroanilides were used, Ala-Ala-Phe-Na was hydrolyzed most rapidly at pH 3.4, Ala-Ala-Ala-Na and Ala-Ala-Phe-Na were hydrolyzed most rapidly at pH 7.0, and Gly-Na, Ala-Na, and Met-Na were hydrolyzed most rapidly at pH 8.9. When b-naphthylamine derivatives were used, Lys-Nap and Arg-Nap were hydrolyzed most rapidly at pH 3.4, Lys-Nap, Trp-Nap and Arg-Nap were hydrolyzed most rapidly at pH 7.0, and Ala-Nap, Trp-Nap, and Lys-Nap were hydrolyzed most rapidly at pH 8.9. After germination, when 4-nitroanilides were used, Ala-Ala-Ala-Na, Gly-Nap, and Ben-Arg-Nap were hydrolyzed most rapidly at pH 3.4. This was not observed before germination. Gly-Na was hydrolyzed most rapidly at pH 7.0 (more than four times the rate before germination). When b-naphthylamine derivatives were used, Tyr-Nap, Ben-Phe-Nap, Ser-Nap, and Cbz-Phe-Nap were hydrolyzed most rapidly at pH 3.4. Trp-Nap, Tyr-Nap, Phe-Nap, Arg-Nap, and Pro-Nap were the five leading substrates at pH 7.0 and 8.9. Garlic enzymes hydrolyze derivatives of 4-nitroaniline and b-naphthylamine of amino acids and peptides differently at different pHs. The same was observed for those of onion.
KEYWORD Garlic; Germination; Protease; Synthetic substrates;
ARTICLE INFO Botanical Bulletin of Academia Sinica, Volume 36 Number 3 July 1995, page 189-194, 6 pages
PUBLISHER Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China