Plant Isoenzymes

Shannon, Leland M.

doi:10.1146/annurev.pp.19.060168.001155

Cited by 154 publications

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“…Whether or not these multiple bands of peptide hydrolase activity represent structurally similar related molecules or different molecules having catalytic activity toward the same substrate must await further purification of these enzymes. Problems in the classification and nomenclature of isoenzymes are reviewed elsewhere (34,35).…”

Section: Resultsmentioning

confidence: 99%

Peptide hydrolases in the brush border and soluble fractions of small intestinal mucosa of rat and man

Kim¹,

Birtwhistle²,

Kim³

1972

J. Clin. Invest.

157

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A BST RA CT Peptide hydrolases, catalyzing the hydrolysis of 13 dipeptides and 5 tripeptides into their respective amino acids, were studied in small intestinal mucosa and other tissues, in man and in the rat.Studies on the subcellular distribution of these enzymes showed enzyme activities in both the soluble and brush border fractions of the rat small intestinal mucosa, the former constituting 80-90% and the latter 10-15% of the total activity. Zymogram studies of peptide hydrolases, in both fractions, yielded multiple bands indicating multiple zones of enzyme activity. With most substrates a rather broad range of enzyme activities was observed in the soluble fraction differing only slightly from substrate to substrate, the exception being when L-leucyl-L-proline was used: this latter led to a zymogram pattern which was quite distinct. The synthetic substrates, L-leucyl-P-naphthylamide and Lleucinamide appeared to be hydrolyzed by two electrophoretically distinct enzymes, different from those hydrolyzing other leucyl-containing peptide substrates.Zymogram patterns of the brush border membrane fraction were quite different from those of the soluble fraction of rat small intestine indicating that enzymes from the two sources may be different. No comparable human data were obtained.Peptide hydrolases in the soluble fractions of various organs from the same species gave similar zymogram patterns, while those from the plasma membrane-bound fractions of different organs in the same species were peculiar to each organ. From these data, it is suggested that peptide hydrolases in the brush border and the soluble fractions of small intestine are distinct enzymes and may play different roles in cellular function.

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Section: Resultsmentioning

confidence: 99%

Peptide hydrolases in the brush border and soluble fractions of small intestinal mucosa of rat and man

Kim¹,

Birtwhistle²,

Kim³

1972

J. Clin. Invest.

157

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“…Many workers have concluded that isozymes play a significant role in clarifying the taxonomy, phylogenetic position and the population variation (Shannon, 1968;Gottlieb, 1982; Schmitz and Kowallik, 1986). Isozymes have also been examined in relation to the environment.…”

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confidence: 99%

Genetic Variation ofzoysiain Taiwan as Analyzed by Isozyme Patterns and Salinity Tolerance

Weng

2002

Plant Production Science

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“…Cutting effects on PPO activity have been observed in tissues such as sweet potato (5,8), and PPO activities have been found in latent or bound forms (7). So-called wounding effects due to the release of phenolic compounds from damaged vacuoles or as a result of fungal infection have also been reported to increase PPO activities (13). The new DOPA-rich activity described here, however, cannot be attributed to microbial contamination, since analysis of tissues from contaminated cultures always showed a much reduced increase in the new activity.…”

Section: Discussionmentioning

confidence: 99%

Ontogeny and Hormonal Control of Polyphenoloxidase Isozymes in Tobacco Pith

Stafford

Galston

1970

Plant Physiol.

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(b) in flasks on a shaker, in liquid solutions of 2I-MW medium (4) with and without added kinetin and IAA. Sections were incubated at about 25 C under constant illumination (about 100 ft-c) for 2 to 7 days. After rinsing with distilled H20, the tissues were extracted directly or after freezing, without apparent differences in activities.Enzyme Extracts. Tissues were ground with sand in a mortar in 50 mm phosphate buffer at pH 6; the ratio of fresh weight to buffer volume was 1:1. After straining through cheesecloth and centrifugation for 15 min at 30,000g the final supernatant was dialyzed against distilled water with continuous stirring overnight at about 5 C. Enzyme activities were generally assayed on unfrozen extracts.

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Plant Isoenzymes

Cited by 154 publications

References 0 publications

Peptide hydrolases in the brush border and soluble fractions of small intestinal mucosa of rat and man

Peptide hydrolases in the brush border and soluble fractions of small intestinal mucosa of rat and man

Genetic Variation ofzoysiain Taiwan as Analyzed by Isozyme Patterns and Salinity Tolerance

Ontogeny and Hormonal Control of Polyphenoloxidase Isozymes in Tobacco Pith

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