Invertase &amp; invertase inhibitor in potato

Schwimmer, Sigmund; Makower, Rachel U.; Rorem, Edward S.

doi:10.1104/pp.36.3.313

Cited by 74 publications

(44 citation statements)

References 13 publications

(8 reference statements)

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“…The first evidence for an invertase inh:lbitor in potato tubers was obtained from kinetic studies on invertase in cru,de extracts (15). The deviat.on fronlinearity beItween enzynme concentratioin anl rate of invertase action was attributed to partial inhibition of invertase act:vitv by an inhibitor in the extracts.…”

mentioning

confidence: 97%

Invertase Inhibitor from Potatoes: Purification, Characterization, and Reactivity with Plant Invertases

Pressey¹

1967

Plant Physiol.

100

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confidence: 97%

Invertase Inhibitor from Potatoes: Purification, Characterization, and Reactivity with Plant Invertases

Pressey¹

1967

Plant Physiol.

100

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“…Schwimmer et al (16) concluded that there was evidence for the presence of an endogenous inhibitor of invertase activity in potato tubers. Pressey (11,12) convincingly demonstrated that such an inhibitor was present, reported on its partial purification, and characterized the inhibitor as a protein with a molecular weight of about 17,000.…”

mentioning

confidence: 99%

“…Several workers (5,9,16) applied equations based on noncompetitive, highly dissociable enzyme-inhibitor complex formation to determine the amount of invertase present in tuber extracts. Pressey (11) mentioned that the reciprocal of enzyme activity plotted against inhibitor concentration after the method of Dixon (1) gave a straight line.…”

mentioning

confidence: 99%

An Examination of Methods Used to Assay Potato Tuber Invertase and Its Naturally Occurring Inhibitor

Ewing¹,

McAdoo²

1971

Plant Physiol.

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Confirming an earlier report, it was shown that the endogenous inhibitor of potato tuber invertase forms an es.sentially undissociable complex with the enzyme. Conse.quently, several previous analyses of potato tuber invertase which were based on equations derived for highly dissociable enzvme-inhibitor complexes are presumed to be in serious error. The complex formation proceeded slowly, requiring approximately 1 day to reach completion at 2 C, and 1 hr at 37 C. Allowing complex formation to reach completion before assaying enzyme activity did not affect the noncompeti. inhibitor complex is actually of low dissociability, then the equations used by previous workers (5, 9, 16) would be in serious error (2, 4). Therefore, it seems worthwhile to examine further the dissociability of the enzyme-inhibitor complex. MATERIALS AND METHODSCrude extracts from potato (Solanum tuberosum L.) tubers were prepared for assay as described by Pressey and Shaw (14), including the use of an Acme Juicerator for homogenization. A shortened form of the procedure outlined by Pressey (12) was followed for partial purification of invertase inhibitor, using only the acid precipitation, fractionation with ammonium sulfate, adsorption on alumina gel, and Sephadex G-100 steps. Invertase purification was accomplished by the procedure of Pressey (12), except that crude extracts were subjected to longer foaming periods in an attempt to inactivate the inhibitor more completely. Enzyme and inhibitor preparations were buffered with acetate at pH 4.75. Pressey's (11) definition of invertase activity was adopted whereby 1 unit is that amount of enzyme which liberates 1 ,umole of reducing sugar per hr under the conditions of the assay.Pressey's (11) assay was employed with slight modifications.The volume of the incubation mixture was reduced to 1 ml. The mixture was 0.1 M with respect to acetate buffer, pH 4.75, and 0.25 M with respect to sucrose. This sucrose concentration gave the optimal reaction rate for the range of enzyme concentrations used in our experiments. The assay was performed at 37 C for 1 hr. The reaction was linear with time throughout the assay period. One milliliter of copper reagent (17), which completely stops invertase activity, was added to terminate the reaction. Tubes were immediately heated for 20 min in a boiling water bath. After cooling, 1 ml of arsenomolybdate color reagent (10) and 7 ml of water were added. Solutions were then mixed and centrifuged 10 min at 500g, and their absorbance was read at 520 nm. Boiled enzyme blanks included as controls did not vary significantly in absorbance from reagent blanks.Foaming of solutions was performed with a VirTis blender (12, 14) set on medium speed. The homogenizing flask was kept in a water bath at 37 C during blending. An alternative method of foaming employed N2 gas bubbled into 0.5 ml of extract through a hypodermic syringe needle, the end of which was cut off square. (Diameter of the needle did not appear to affect results.) All solutions foamed were 0.1 M in aceta...

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“…The Lin genes are located on the ninth and tenth chromosomes. An endogenous protein called an invertase inhibitor suppresses invertase activity in potato (Schwimmer et al, 1961). It also inhibits invertase activity in tomato (Jin et al, 2009).…”

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confidence: 99%

Gene expression patterns of invertase gene families and modulation of the inhibitor gene in tomato sucrose metabolism

Zhang

Zhang²,

Jiang³

2013

Genet. Mol. Res.

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ABSTRACT. Patterns of gene expression in the different types of sucrose metabolism in the tomato are highly variable and heritable. This genetic variation causes considerable functional differences. We examined the patterns of expression of invertase (Inv) gene families and an invertase inhibitor (INH) gene involved in elongating roots, hypocotyls, and fruit of the tomato (Lycopersicon esculentum cv. Micro-Tom and L. chmielewskii) through a real-time quantitative PCR analysis. We found that the Lin6 gene plays an important role in the vegetative growth stage. Lin5 and Lin7 did not express in Micro-Tom, but did express in L. chmielewskii. Overall relative expression levels of sucrose Inv gene families were significantly lower in L. chmielewskii during the reproductive growth stage than in Micro-Tom, being up to hundreds of times lower. It was not expressed in the dissepiment in L. chmielewskii. We suggest that differences in sucrose accumulation in tomato fruit is mainly due to differentially expressed invertase gene families at the later fruit growth stages.

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Invertase & invertase inhibitor in potato

Cited by 74 publications

References 13 publications

Invertase Inhibitor from Potatoes: Purification, Characterization, and Reactivity with Plant Invertases

Invertase Inhibitor from Potatoes: Purification, Characterization, and Reactivity with Plant Invertases

An Examination of Methods Used to Assay Potato Tuber Invertase and Its Naturally Occurring Inhibitor

Gene expression patterns of invertase gene families and modulation of the inhibitor gene in tomato sucrose metabolism

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