Disease relevance of H-D-Phe-pip-arg-pna

• Chromogenic substrate (S-2238) prothrombin assay in prothrombin deficiencies and abnormalities. Lack of identity with clotting assays in congenital dysprothrombinemias [1].

High impact information on H-D-Phe-pip-arg-pna

• Its activity, however, is altered to various extents toward the following substrates: H-D-phenylalanyl-L-pipecolyl-L-arginine paranitroanilide (S 2238), fibrinogen, factor V, protein C, and antithrombin III [2].
• The presence of the high affinity gamma' chain site on fibrinogen molecules did not inhibit fibrinogen conversion to fibrin as assessed by thrombin time measurements, and thrombin exosite binding to fibrin at either site did not inhibit its catalytic activity toward a small thrombin substrate, S-2238 [3].
• Activation was monitored using a chromogenic substrate (S-2238) to detect both II(a) and MzII(a) active site formation and SDS-PAGE to detect Pre2-F1.2 as well as II(a) and MzII(a) [4].
• Like purified lung TM, rat glomeruli extracts accelerated the hydrolysis by activated protein C of the chromogenic substrate S-2238 in the presence of 10 nM thrombin, as determined by spectrophotometry [5].
• After removal of CSA and incubation with thrombin and purified protein C, thrombomodulin-dependent protein C activation was measured with an S-2238-based kinetic chromogenic assay [6].

Biological context of H-D-Phe-pip-arg-pna

• However, in this case the latent thrombin activity is progressively diminished during the heating process in terms of both clotting activity and hydrolysis of the amide substrate H-D-Phe-Pip-Arg-pNA [7].
• Synthetic substrates have recently been developed for the assay of several of the proteolytic enzymes required for blood coagulation, One of these substrates, S-2238, is specific for thrombin and hence can also be used to measure antithrombin-heparin co-factor (AT-III) [8].
• The catalytic site of thrombin was not perturbed by the synthetic peptide as H-D-Phe-Pip-Arg-pNA hydrolysis (amidase activity) was not affected [9].
• Here we show that suramin binds to human alpha-thrombin inhibiting both the hydrolysis of the synthetic substrate S-2238 (IC50 = 40 microM), and the thrombin-induced fibrinogen clotting (IC50 = 20 microM) [10].
• Human and bovine alpha-thrombins (greater than 90% alpha form) with high fibrinogen clotting activities (approximately 3,000 U.S. units/mg protein) exhibit similar Michaelis menten kinetics with the p-nitroanilide tripeptide substrates Tos-Gly-Pro-arg-pNA (Chromozym-TH) and D-Phe-Pip-Arg-pNA (S-2238) [11].

Associations of H-D-Phe-pip-arg-pna with other chemical compounds

• Kinetic analysis showed that suramin acts as a non-competitive inhibitor decreasing Vmax without changing the Km for S-2238 hydrolysis [10].
• Hydrolysis of the synthetic substrate S-2238 was enhanced (35%) in 2 m urea and gradually abolished at higher concentrations, while HHP (270 MPa) inhibited the enzyme's catalytic activity by 45% and abolished it when 1.5 m urea was also present [12].
• Based on the individual kinetic parameters calculated here, bradykinin is classified as a weak competitive inhibitor against hydrolysis of S-2238 and of a PAR4-like peptide [13].
• The extent of ATIII binding to heparin in each experiment was assayed using a chromogenic substrate for ATIII, S-2238 [14].
• 6. The enzyme had weak amidolytic activities toward CBS 65-25, but it showed no activities on S-2266, S-2302, thrombin substrate S-2238, plasmin substrate S-2251 or factor Xa substrate S-2222 [15].

Gene context of H-D-Phe-pip-arg-pna

• Amidolytic activity with the "thrombin" substrate H-D-phenylalanyl-L-pipecolyl-L-arginine-p-nitroanilide dihydrochloride (S-2238) was evident when streptokinase, plasminogen (0.24 microM), and prothrombin (1.5 microM) were incubated in buffer [16].
• Two brands (E, F) contained no protein S, additionally one brand contained no protein C. Two preparations exhibited high amidolytic activities, especially towards the thrombin-sensitive chromogenic substrate S-2238, in vitro [17].
• Cerastobin had thrombin-like activity, producing fibrin from fibrinogen and also hydrolyzing chromogenic substrates for thrombin such as 2AcOH.H-D-CHG-But-Arg-pNA (CBS 34.47) and H-D-Phe-Pip-Arg-pNA (S-2238) [18].
• This was documented by an increase in the Michaelis constant from 8.3 microM for thrombin alone to 19.5 microM for thrombin-TM with the chromogenic substrate compound S-2238 in the presence of 1 unit/mL protamine [19].
• The interaction of monovalent cations with activated bovine plasma protein C (APC) has been examined by kinetic methods, with H-D-phenylalanylpipecolylarginine-p-nitroanilide (S-2238) being employed as the substrate [20].

Analytical, diagnostic and therapeutic context of H-D-Phe-pip-arg-pna

• Antithrombin III (AT-III) was determined functionally using chromogenic substrate (S-2238) and immunologically using radial immunodiffusion (RID) in plasma and serum from 115 blood donors [21].
• We have developed a novel method using the synthetic substrate S-2238 and hirudin, a tight-binding inhibitor of thrombin, that allows for the active-site titration of thrombin at concentrations as low as 20 pM, with an error of < or = 5% [22].

References