Inhibition of tonoplast ATPase from etiolated mung bean seedlings by N-bromosucciminide and 2-Hydroxy -5-nitrobenzyl bromide

• Main Authors: May-Whei Lin, 林美慧
• Other Authors: Rong-Long Pan
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/02020587506110569882

碩士 === 國立清華大學 === 輻射生物研究所 === 81 === Two modifying reagent, N-bromosuccinimide (NBS) an d 2-hydroxy-5-nitrobenzyl bromide (HNBB), could inhibi t the hydrolysis activity of tonoplast ATPase from eti olated mung bean. Under our condition, HNBB is specifi c for the modification of tryptophan, while NBS could react with several residues besides tryptophan. the in activation of ATPase by HNBB was concentration- and ti me-dependent. From the semilogarithmic plot of time co urse of the inactivation, the reaction order of inacti vation was calculated as 0.973, indicating that at lea st one tryptophan was esstential to the enzymatic acti vity of V-ATPase. Kinetic analysis shows that Km but n ot Vmax of ATPase was changed by NBS, while the Vmax b ut not Km of the enzyme was decreased by HNBB. ATP and its analogs could protect ATPase against NBS but not H NBB, implying that modification sites of NBS and HNBB are not same.