Disease relevance of Benzoylphenylalanyl-alanyl-proline

• When full capillary recruitment was achieved (at Qb > 70 ml/min/g lung wet weight), further Qb elevations failed to increase Amax/K(m), but decreased BPAP hydrolysis, denoting shorter transit times through the fully recruited capillary bed [1].

High impact information on Benzoylphenylalanyl-alanyl-proline

• Here we used the biologically inactive ACE substrate (3)H-labeled benzoyl-Phe-Ala-Pro ([(3)H]BPAP) to quantify CC-ACE activity in 10 patients by means of the indicator-dilution technique [2].
• An inhibitor of angiotensin-converting enzyme, SQ 20,881, depressed BPAP metabolism by 50%, while perfusion of the bronchial circulation with glutaraldehyde reduced metabolism to a basal level [3].
• We estimated single-pass translobar hydrolysis and calculated the corresponding Amax/K(m) values of the synthetic ACE substrate 3H-benzoyl-Phe-Ala-Pro (BPAP), under first-order reaction conditions, in isolated blood-perfused dog lung lobes [1].
• Angiotensin-converting enzyme (ACE, E.C. 3.4.15.1) activity has been documented in eight cultures of fibroblasts with the ACE substrates benzoyl-phe-ala-pro and hippuryl-his-leu [4].
• The rats of hydrolysis of benzoyl-phe-ala-pro by fibroblasts and by endothelial cells differ at high substrate concentrations; therefore, the ACE activity in fibroblasts may be due to either a different isoenzyme of ACE of a different accessibility to substrate [4].

Biological context of Benzoylphenylalanyl-alanyl-proline

• The first method involves two determinations of Michaelis-Menten constants Km and Amax (product of Vmax and lung capillary plasma volume) of endothelial-bound ACE for BPAP [5].
• Angiotensin converting enzyme activity was 2.8 +/- 0.03 Units/10(6) cells (N = 19; 1 Unit: amount of enzyme required to metabolize 1% of substrate, benzoyl-Phe-Ala-Pro, in 1 min under conditions of first order reaction kinetics) in confluent monolayers and 2.31 +/- 0.06 Units/10(6) cells (N = 20) in homogenates [6].
• For each determination of Km and Amax, two consecutive bolus injections of BPAP were given into the right atrial catheter, the first containing 0.1 and the second 1622 nmol of substrate, producing first order and mixed order substrate concentrations, respectively, in the pulmonary circulation [7].

Associations of Benzoylphenylalanyl-alanyl-proline with other chemical compounds

• We applied Michaelis-Menten kinetics in simultaneous estimations of apparent constants Km and Amax (product of Vmax and microvascular plasma volume) of these two enzymes for the substrates 3H-labeled benzoyl-Phe-Ala-Pro and 14C-labeled 5'-AMP, respectively, in vivo [8].

References