What is the clinical evidence from this study?

Intervention: Fluorimetric assay using Hip-His-Leu. Primary outcome: Standardization of fluorimetric method to measure tissue ACE activity.

What question did this study set out to answer?

To standardize and validate a fluorimetric assay using Hip-His-Leu as a substrate to quantify angiotensin-converting enzyme (ACE) activity across various rat tissues.

July 1, 2000Brazilian Journal of Medical and Biological ResearchOpen Access

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

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Key result

A fluorimetric method using Hip-His-Leu as a substrate was successfully standardized to easily and efficiently assay ACE activity in rat tissue samples homogenized in borate buffer.

Key Points

To standardize and validate a fluorimetric assay using Hip-His-Leu as a substrate to quantify angiotensin-converting enzyme (ACE) activity across various rat tissues.
Assessed tissue homogenate interference on o-phthaldialdehyde-His-Leu adduct fluorescence across diverse rat organs, testing a 10-fold dilution in assay buffer for interfering tissues.
Determined assay specificity using 3 µM enalaprilat (MK-422) and established linear kinetic parameters across incubation times (30–90 min) and protein ranges.
Evaluated the impact of borate buffer versus phosphate buffer, detergent addition, and storage stability at -20°C and -70°C for at least 30 days.
Homogenates from lung, renal cortex, and renal medulla exhibited significant baseline fluorescence interference, which was fully corrected by a 10-fold buffer dilution.
Linear product formation occurred across tissue-specific ranges, and ACE activity in borate buffer surpassed that in phosphate buffer due to reduced substrate hydrolysis.
Enalaprilat (3 µM) selectively inhibited enzyme activity, and homogenates remained stable at -20°C or -70°C for at least 30 days without loss of activity.

Structured PICO

Population

Rat tissue samples (lung, renal medulla and cortex, liver, ventricles, adrenals, aorta, atrium)

Intervention

Fluorimetric assay using Hip-His-Leu as a substrate in borate buffer

Outcome

Measurement of tissue angiotensin-converting enzyme (ACE) activitysurrogate

This study provides a standardized, efficient fluorimetric method for measuring ACE activity in various rat tissues using Hip-His-Leu as a substrate.

Discussion

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Implication

Interference from lung and renal homogenates requires assay correction; leaves open broader validation for tissue ACE measurement.

Cite This Study

Oliveira et al. (2000) studied this question. Fluorimetric assay using Hip-His-Leu was evaluated on Standardization of fluorimetric method to measure tissue ACE activity. A fluorimetric method using Hip-His-Leu as a substrate was successfully standardized to easily and efficiently assay ACE activity in rat tissue samples homogenized in borate buffer.

synapsesocial.com/papers/6a6bb8e978a09e5ab7b3b599 https://doi.org/10.1590/s0100-879x2000000700005

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Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

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